One Steve Limit/Real Life

Inversions of, and exceptions to, a in  include:

"Dave Gorman (on Letterman): Yes, I have an idea for a new show. It's called "Are you Osama Bin Laden?""
 * Marie of Roumania (sic) was born in Germany and became queen of Yugoslavia. On the other hand, her mother, Marie of Edinburgh, ruled Romania. Hilarity Ensues.
 * George Foreman named all five of his sons George (George Jr and George III to VI), and one of his five daughters Georgetta.
 * On 30 Rock, Tracy Jordan named his children Tracy Jr. and George Foreman.
 * The Romans were pretty bad about breaking this rule. But the Julio-Claudian dynasty took the cake.
 * The famous Julius Caesar shared his full name (Gaius Julius Caesar) with his father, grandfather, and quite a lot of other relatives, among them his great nephew known as Augustus. This makes their history just a little confusing sometimes.
 * Even worse for women. Officially, a daughter's name was just the feminine version of the family name—Julius Caesar's sister, daughter, and paternal aunt would all be named "Julia". In practice, sisters would be distinguished by nicknames or other variants (a beauty might be called "Helen", a girl born on Lesbos might be called "Lesbia", etc.); but if you find a statue of "Agrippina", it can be hard to figure out which of Agrippa's many famous female descendants it represents.
 * And to further confuse things, his adopted son (originally named Gaius Octavius) changed his name in accordance to the named-after-your-father tradition, so both Caesar and Augustus actually went by the name Gaius Julius Caesar; though the latter, as an adoptee, had the optional Octavianus.
 * Then there were also the three emperors Tiberius, Claudius, and Nero, who where the third, fifth, and sixth emperors beginning with Caesar. The first two were actually names "Tiberius Claudius Nero", but despite other claims, Neros full name was Nero Claudius Caesar Augustus, which also wasn't much better.
 * In addition Julius was assassinated by Marcus Brutus, who shared a name with his ancestor who was instrumental in overthrowing the last king of Rome.
 * On the whole, the Romans weren't very big on inventive names. In classical times, their list of "acceptable first names" had been boiled down to ~20. This is, if they didn't outright number them through.
 * Mainland China has rather simple, conventional naming traditions when compared to other Chinese-speaking nations/areas/whatever such as Hong Kong and Taiwan. This essentially means it's rather likely that two or more people will share the same-sounding first and last names. This is generally averted with either calling them "male [name here]" and "female [name here]", or, if there are any of the same gender, making references to the different characters in those names. Of course, people sharing the exact same names, calligraphy-wise, in the same classroom are not unheard of...
 * Let's not forget many monarchical dynasties that violate this rule constantly, eg. the Bourbons used the name Louis so often that there was a Louis XVIII of France. See also the Ptolemies of Egypt almost all of whom were called Ptolemy, or in the rare case of prominent females, Cleopatra (VII being the famous one).
 * Not to mention those eighteen Louis were only the ones who became kings. Don't forget Louis XIV, son of Louis XIII, was such a long-living bugger that he outlived not only his son Louis but also his grandson Louis making Louis XV his great-grandson who also named his son Louis and... you get the idea.
 * The House of Reuss, wherein EVERY MALE MEMBER of the family was named Henry/Heinrich.
 * France also provides us with the War of the Three Henrys, a three-sided Civil War in which the Royalist party was led by King Henri III, the Catholic League was led by Henri, the Duke of Guise, and Navarre was led by Henri of Navarre. Henri of Navarre won, becoming Henri IV.
 * There are at least two historic sultans named Suleiman. "Suleiman the Magnificent" is the one who conquered Europe all the way to Vienna.
 * King George V had four sons living to adulthood, three of whom had "George" somewhere in their cluster of Christian names. However, the first went by David (Edward VIII), the second by Albert, and the fourth used George as his first name. However, when Albert became king in 1936, he, following the course of his grandfather Edward VII, declined to use Albert as his regnal name in recognition of his great-grandfather Albert, Prince-consort. Instead, Albert became George VI, to emphasize continuity with his father's long reign - which meant that the royal family now contained two brothers named King George and Prince George.
 * Louis XVIII (Louis Stanislas Xavier) of France was a younger brother of Louis XVI (Louis August).
 * Henry VIII was married to, in order, Catherine of Aragon, Anne Boleyn, Jane Seymour, Anne of Cleves, Catherine Howard, and Catherine Parr. Three names for six wives.
 * Mitch Hedberg used to tell a joke about his ex girlfriend named Lyn and his current girlfriend (who later became his wife, and even later his widow) named Lynn.
 * Is your name Dave?
 * Karl Freiherr vom Stein was replaced in his post as Prussian statesman in 1807 for about half a year by Karl Reichsfreiherr vom Stein zum Altenstein.
 * Karl Reichsfreiherr vom und zum Stein was Prussia's premier minister from 1807 to 1808. Karl Reichsfreiherr vom Stein zu Altenstein was co-leading minister (along with Count Dohna-Schlobitten) from late 1808 to 1810. The latter was however generally known as Altenstein (and signed that way).
 * In rural Northern Ireland, people with the same name would be differentiated by the name of their father, resulting in conversations something like this: "So ah wuz talkin' teh Stephen the other day..." "Which Stephen?" "Wullie's Stephen - ye know, th' one that married Billy's Helen."
 * The royal house of Prussia would often do something similar in the case of duplication. For instance in the late 18th century, King Frederick William III had a younger brother called Louis, but there was another Prince Louis, son of Prince Ferdinand (the youngest brother of King Frederick the Great), who was therefore called Prince Louis Ferdinand, even though Ferdinand was not one of his Christian names. Frederick William III had another brother called William as well as a younger son called William (later William I of Prussia and Germany). The former was sometimes called "Wilhelm Bruder" (William brother).
 * This trope is a rule in many showbiz unions, forcing those with common names to don pseudonyms (many of which are Line-of-Sight Name):
 * David McDonald alias David Tennant
 * Michael J. Fox, whose fake middle initial stands for nothing
 * Diane Hall, who took her mother's maiden name (Keaton)
 * And speaking of people named Keaton, Michael Keaton is actually Michael Douglas. He just renamed himself "Keaton" because there was already a prominent actor named Michael Douglas.
 * Stewart Granger's real name was James Stewart.
 * In an extreme case, actor/comedian Jm J. Bullock was forced to change the spelling of his name because a 'Jim J. Bullock' was already enrolled in the union.
 * David X. Cohen is named thus because there was an existing David S. Cohen.
 * Singer Katy Perry changed her last name, Hudson, so she wouldn't be confused with actress Kate Hudson.
 * Katy Perry (or at least her 'people') also attempted to sue an Australian woman whose name is Katie Perry because Katie Perry has a clothing brand with her name never mind the fact that she (Katie) had started the brand years before Katy had become famous.
 * Averted in the current squad of Real Madrid, where shirt number 9 belongs to (Cristiano) Ronaldo. Until 2007 the owner of the number was the Brazilian Ronaldo (Luiz Nazario da Lima). Also, because of the Brazilian Ronaldo, Ronaldo de Assis Moreira has been using the nickname Ronaldinho. To go further, the Brazilian Ronaldo played under the name Ronaldinho too, in Atlanta, 1996, to distinguish him from teammate Ronaldo Guiaro.
 * If you're Korean, chances are that your last name is either Kim, Park, or Lee.
 * The joke is that if you throw a rock off the mountain near Seoul you'll hit someone with one of those names.
 * The Chinese are not quite as bad as the Koreans, but there is still a roughly 1-in-4 chance that any random Chinese you meet will have the family name Wang/Wong, Li, or Zhang.
 * The Swedish Kenneth Club. Exactly What It Says on the Tin.
 * Project Steve is a list of scientists who believe in evolution, all of whom are named Steve (or a variant thereof) in honour of Steven Jay Gould.
 * Averted by Apple Computer, which was founded by two guys named Steve.
 * Sebastian Vettel started driving for Formula One race team Scuderia Toro Rosso (STR) in late 2007. For 2008, his teammate was Sébastien Bourdais. When Vettel moved to STR's sister team Red Bull Racing in 2009, he was replaced by Sébastien Buemi as Bourdais' teammate. Sadly, when Bourdais was fired mid-2009, his replacement was named Jaime and not a variant of Sebastian. However, STR at the end of 2009 STR attempted to have rallying champion Sébastien Loeb test for them, presumably as a possible driver for 2010, though Loeb was unable to obtain the Super License required to race in Formula 1.
 * And now for One Steve Limit-lite: One of Mercedes's drivers is Nico Rosberg, and one of Williams's drivers is Nico Hulkenberg.
 * In the past, there was Mika Hakkinen and Mika Salo.
 * And in the past brothers have competed in F1-Michael and Ralf Schumacher.
 * Timo and Tommi Makinen (no relation), both champion rally drivers, both nicknamed the "Flying Finn".
 * When groups of friends, workmates, classes or other organised gatherings have some shared names, they're likely to find ways to differentiate people fairly quickly to avoid confusion.
 * There was a Facebook group about how if Taylor Swift and Taylor Lautner got married, back when they were dating, they would both be Taylor Lautner.
 * Mike Greenberg and Mike Golic, co-hosts of ESPN's "Mike and Mike in the Morning". They go by Greenie and Golic.
 * Averted by the team of Bob Gale and Bob Zemeckis, who simply went by the collective moniker "Bob & Bob" when they worked together on the Back to The Future films.
 * Have you tried to read a history book about the Hundred Years War? There are about a dozen different guys that are named Charles (Charles VI and VII, Charles of Anjou, of Aragon, Charles le Mauvais, etc)...which makes it kinda difficult to follow.
 * Dave Gorman and his friend (also named Dave) had a drunken bet going. Namely that there was another "Dave Gorman" an assistant manager for Fife. So they travelled several hundred miles from London to Fife to meet him. When they got there, they asked the manager if he knew any other Dave Gormans. "No. Well, wait, my Dad is also Dave Gorman. Oh yeah, and my son is Dave Gorman too." Dave Gorman (the original) happened to be a stand up comedian...so he travelled internationally to find other Dave Gormans and then he made his own show called "Are You Dave Gorman?


 * Dave Gorman's friend... "Dave" Danny Wallace?
 * Mr & Mrs. Kelly Hildebrandt. They met when she looked up people with her last name on Facebook.
 * Many large creative projects, like creating a stage show or making a film, will include lots of people, and occasionally there are some who share the same name. For example, in all his films since Batman Begins, Christopher Nolan has worked with special effects supervisor Chris Corbould.
 * Early in the station's life, UPN ran an ad campaign based on the fact that three of their exclusive shows starred people named Richard: Platypus Man with Richard Jeni, Marker with Richard Grieco, and Legend with Richard Dean Anderson. How successful was this ad campaign? Note that none of the three shows have a page at this time.
 * Also on UPN was Star Trek Voyager, which had Robert Beltran, Robert Duncan McNeill, and Robert Picardo as part of the cast. Reportedly they went by Rob, Robert and Bob respectively to keep things straight.
 * When Michael Caine decided to act under the name Michael Scott, he was informed the name was already taken. He chose the last name after seeing a theater was showing The Caine Mutiny. He later joked that he might have been known as "Michael 101 Dalmatians" if he looked in the other direction.
 * Harrison Ford was worried that he shared the same name as a silent movie star, but his fame as since eclipsed that of the original Harrison Ford.
 * When citing a list of United States presidents that only gives last names, presidents with similar names will often be differentiated with nicknames and variations. For instance, referring to "Roosevelt" often means Theodore Roosevelt, whereas one who is referring to Franklin Delano Roosevelt will refer to him as FDR. More recently, simply saying "George Bush" would tend to refer to the more recent one by default (though many will call him "George W. Bush" specifically anyway), while someone referring specifically to George Bush senior would likely call him "George H.W. Bush".
 * Subverted by Lyndon B. Johnson / Andrew Johnson (who became presidents roughly a century apart from one another), and Grover Cleveland (who really was the same guy who just got elected twice non-consecutively).
 * In Mexico there's the "C.U.R.P." which is an ID number based on your name, birthplace and birthday, if your name is "José" (for males) or "María" (for females) then that name's ignored for curp purposes unless it's your only name (it's actually more common for people in Mexico to have two names than only one). For added fun you can ask any "María" if her full name is "María Guadalupe", you have a 50% chance to get it right.
 * The C.U.R.P.'s code is based on your name, first and second surnames, plus the date of birth. Given that there are a lot of surnames in Mexico that are really common, even to the point of making jokes (e.g. Juan Pérez), it's really common for people to have a repeated code (ex. GOHP130459 = GOnzález Hernández Pablo 13(d)/04(m)/59(y)), in which case they add an extra number (ex. GOHP1304592)
 * In the Canadian House of Commons, when there's a standing vote, MPs are called by their last names—unless they share a last name with (or have a similar last name as) another MP, in which case the name of the riding (constituency) is appended: for example, Ms. Davies (Vancouver East) and Mr. Davies (Vancouver-Kingsway). Fate dictates that the longer and more unwieldy your riding name is, the more likely you are to share a name with another MP, just to make life difficult for the clerks; during one troublesome period, there was a M. Guimond (Montmorency—Charlevoix—Haute-Côte-Nord) and a M. Guimond (Rimouski-Neigette—Témiscouata—Les Basques).
 * Winston Churchill was a best-selling American novelist at the beginning of the twentieth century. When the British Winston Churchill began his public career, he identified himself as Winston S. Churchill so he wouldn't be confused for the then better-known author.
 * The town of Phil Campbell, Alabama is the home of the Phil Campbell Convention, which hosted 22 Phil Campbells and 1 Phyllis Campbell when it was first held in 1995. When the town took a direct hit from an F-5 tornado in April 2011, guests for that year stepped up to provide help.
 * Chris Colfer and Darren Criss who play Kurt and Blaine on Glee. It's been said that if they got married, Chris's name would be Chris Criss, or Chris Squared.
 * American Football players Roy E. Williams and Roy L. Williams who, to confuse matters even further, both played for the Dallas Cowboys at the same time. Luckily since one was a Wide Receiver and the other Safety they were never on the field at the same time (although the temptation to use the WR as an extra Safety in "prevent" defences must have been quite high...)
 * A startling example was Romanian dictator Nicolae Ceausescu, who had a younger brother, also called Nicolae. Supposedly their drunken father announced the name at the younger child's christening, forgetting that he already had a son with that name.
 * During Finnish Presidental Election in 2012, there were three people running named Paavo; Lipponen, Väyrynen and Arhinmäki. None of them made it to the second round.
 * At the 1996 Jeopardy! Tournament of Champions, two of the finalists were Michael Dupee and Michael Daunt. Dupee, the eventual winner, spent the finals being called "Mike" to avoid confusion.
 * In the 2008 Teen Tournament, the final two games featured two Rachels, so one went by "Steve" (really!).
 * It's been said that Star Trek did so well because it had good Genes. Eugene Wesley Roddenberry (Senior), and Eugene Lee Coon.
 * The above is more punny when you realize the Greek prefix "eu-" does literally mean "good". The name Eugene is Greek in origin and translates to "well-born".
 * There's the Galton-Watson process in mathematics, which investigates the extinction probability of family names. Francis Galton came up with it because his contemporary Victorians were concerned about great aristocratic lines dying out. It shows how the number of names falling (in the absence of new ones) is inevitable given time. And sure enough, countries which have been using surnames extensively for a long time (like China) now have relatively few different last names, while countries which adopted them more recently (like much of Europe) have many more.
 * The Dave Thomas who founded the "Wendy's" fast-food chain is not the Dave Thomas from SCTV.