In Dublin's Fair City

In Dublin's fair city,
Where the girls are so pretty,
I first set my eyes on sweet Molly Malone,
As she pushed her wheelbarrow
Through streets broad and narrow,
Crying, "Cockles and mussels, alive, alive oh"!

—~~"Molly Malone"~~ "The Tart With the Cart", traditional Irish folksong

Dublin (From the Irish "Dubh Linn" meaning "Black Pool" but it's official Irish name is "Áth Cliath" meaning "The Hurdled Ford") is the capital of Ireland, the third-largest Irish city after New York and Boston, and the largest city on the island with a population of about 1 million, including suburbs, and 1.6 million including the population of surrounding counties.

Officially, Dublin celebrated its millennium in 1988 (making the city a spry 1030 at time of writing), but that was just a brazen excuse to hold a party: the Vikings established a stronghold in the Liffey River back in 841 (and even before that there was Eblana). Dublin was an important Hiberno-Norse kingdom for centuries, before ~~some different French accented Vikings~~ the Normans arrived and turned it into the centre of English (and later British) power in Ireland for centuries.

Dublin is famous for its writers (especially James Joyce), musicians, Georgian architecture and its pubs. Indeed, the St. James's Gate Brewery (the home of Guinness, the beer that drinks like a meal) is the most popular tourist attraction in the city...

Perhaps surprisingly, Dublin turns up pretty infrequently in Hollywood versions of Ireland; Hollywood seems to prefer picturesque bucolic Irish villages. The reverse is true of Irish-made films and TV shows, almost all of which are set in Dublin - think like (English) Canadian Series and Toronto, but even more so. This is mostly due to fact that the majority of Irish production companies are based in Dublin and it makes it logistically easier to set a film or tv series in Dublin as opposed to Cork, Limerick or Galway.

Northside vs. Southside

The River Liffey divides Dublin in two, and a good thing that it does, because we don't want those [West Brits/scumbags] (delete as appropriate) from the other side over here.

Note that there are no parts of Dublin officially named 'the Northside' or 'the Southside' - they are geographical expressions, a bit like the 'Deep South' in America. Trust me, everyone will know what you mean.

The Northside is traditionally poorer, more Catholic and, to some, more 'Irish' - it is the part you see in Roddy Doyle films. The Southside is historically richer, more cosmopolitan and more Anglophile (hence the insult 'West Brit'). Northsiders play Gaelic sports and soccer; Southsiders play rugby, which is an upper middle class sport in Ireland. Southsiders see Northsiders as druggies and muggers, Northsiders see Southsiders as... well Upper Class Twit is a very much cleaned up version.

Each side makes fun of the other's accent. I mean, no one really talks like that - roysh?

Postal codes on the Northside are odd; on the Southside, even.

Dublin 4 (D 4) is so Southside that even other Southsiders laugh at people from there: a popular series of books starring a D 4 character named Ross O'Carroll-Kelly (both an Upper Class Twit and a Jerk Jock) are a major hit in Ireland.

The headquarters of Ireland's main television service, RTÉ, are located in the Dublin 4 district, and until around the 1990s, most Oar-Tee-Eee presenters had a Dublin 4 accent - apart from Dustin, the children's TV puppet turkey who took his Northside accent to the Eurovision Song Contest in 2008.

Dubliners vs. Corkonians

Cork is the second city in Ireland (not including Belfast), and the largest county. It also has the most jingoistic inhabitants. Corkonians like to think of their city as the real capital of Ireland - culturally, and at sport at least, and carry on a strong—but entirely one-sided—rivalry with Dubliners. By and large the "feud" is little more than a cliché, most Corkonians and pretty much all Dubliners just ignore it. The only exception is when it comes down to sport, but even here the Corkonians are much more enthusiastic about the whole feud thing than the Dubs. Notably, the Northside/Southside divide also exists in Cork. However, South Corkonians are in no way the same as South Dubs.

The Spire of Dublin

To celebrate the other millennium the city set up a 393 ft tall metal spire in the middle of O'Connell Street. It's... well, it's tall and metal and pointy, and possibly not the best idea to build in a city with a heroin problem. Still the Spire has inspired a few affectionate nicknames, many of them even printable ('the stiletto in the ghetto' or the 'stiffy on the Liffey' for instance).

Dublin in fiction

Film

Literature

Ross O'Carroll-Kelly
Ulysses
- And Dubliners, natch. And Finnegans Wake. And parts of Portrait of the Artist as a Young Man. Basically, (almost) everything James Joyce ever wrote.
Strumpet City
Many of Marian Keyes's books.
Artemis Fowl
The Mammy, by Brendan O'Carroll.

Live-Action TV

Raw
Fair City, Ireland's only soap opera

Western Animation

The Simpsons 2009 episode "In the Name of the Grandfather". Notable for a non-Irish production, especially since it Deconstructed most of the tropes associated with Ireland from outsiders.