Shown Their Work/Tabletop Games


 * GURPS is famous for this. Writers efforts to provide accurate stats for the real world lead to pages worth of citations and examples in many 4th Edition books. They also have been known to hire people that know what they're talking about as advisers, altering and scrapping sections of the rules in order to allow better simulation of reality. Notes that appear alongside the official rules often include notes on how to make the game even more realistic, though notes to the effect that using more realistic rules might bog down the game typically accompany them.
 * This got them in legal jeopardy in 1990, when an over-zealous warrant led to every computer at the firm being confiscated by the Secret Service due to ongoing research at the company for a Cyberpunk genre book. The author had consulted with a few real life hackers, but the book was hardly a 'handbook for computer crime' as one misinformed agent said. It led directly to the creation of the Electronic Frontier Foundation.
 * Actually, the raid occurred because one of the people working at SJ Games happened to have a pirated phone company book on a machine in his home. The overly-reactive raidand subsequent founding of the EFF did indeed occur; it's just that the manuscript was picked up while the Secret Service was in the building. It didn't help that they wouldn't immediately disclose the reason for the raid, leading those working at the company to the most immediate conclusion (that a sourcebook on hacking had brought down the wrath of some people not known for their affection towards BBS operators).
 * Ars Magica from Atlas Games has several supplements whose entire purpose is to Show Their Work, most notable for this being Art et Academe. Most of the authors have some qualification in Medieval History or a similar topic.
 * Warhammer 40000 goes into this at points when they can justify it. For example, Lasguns are only nonrealisticly displayed in art and video games because they would otherwise be really boring. That they make noise and light is generally explained by psychic influences. On the other hand, it might be that 40k really does have Frickin' Laser Beams, and the Mechanicum just doesn't know what they're doing.
 * D20 Modern's economic system is extremely abstract due to the sheer complexity of the economic world (which causes some players no end of grief) but interviews and statements by the designers indicate the level of thought and detail that went into its creation. Why does it hurt your Wealth Bonus less to buy a house than other, similarly expensive things? Because the boost in your credit score received by being a homeowner with a mortgage would help you if you needed to take out a loan or apply for a credit card.
 * Dungeons and Dragons, interestingly enough. While it's traditionally infamous for many really bizarre things, starting with Gary Gygax's ideas of ballistics and weapon weight tables, many authors and designers had experience in fields that turned out to be relevant - and it shows.
 * Bruce R. Cordell earned a degree in Environmental, Population, and Organismic Biology from the University of Colorado. Hence the greatness of The Illithiad.
 * Ed Greenwood, the author of Forgotten Realms, is a librarian and used to fence. Many of Ed's original players either worked in breweries or brewed their own, which also shows - in his sourcebooks there are whole lists of local beverages - not just names, but the specifics of how it tastes, what it was made of and (sometimes) who tend to drink this.
 * Elaine Cunningham is a former music teacher and thus really can sing and play harp. Her hobbies include folklore/mythology and history. Anyone who did read a single novel of her could notice the results.