I recently unearthed a pile of funny things that I didn't know existed in (and about) Wikipedia. Most of them are Wikipedia Essays or other obscure jokes from the administrators.

• 1984
• Association of Geriatric Editors
• Assume Bad Faith
• Complete Bollocks
• Don't stuff beans up your nose
• Newcomers are delicious, so go ahead and bite them, a response to Please do not bite the newcomers
• List of really, really, really stupid article ideas that you really, really, really should not create
• Deleted Articles with Freaky Titles
• Don't feed the Administrators
• Editing Under the Influence
• The five steps of Wikipedian spammer grief
• Please be a giant dick, so we can ban you, a response to Don't Be a Dick
• God: Valuable Wikipedian, or disruptive editor with a history of sockpuppetry?
• Don't delete the main page
• Argumentum Ad Jimbonem
• Millionth Topic Pool, and perhaps even funnier, the Last Topic Pool
• No angry mastodons
• No climbing the Reichstag dressed as Spider-Man
• Unusual Articles (warning: may consume untold hours of your time)
• OMGcom
• Primogeniture
• Requests for Edit Wars - somewhat of a Wikipedia editor inside joke
• Drop the stick and back slowly away from the horse carcass
• Have a nice cup of tea and sit down
• Beware of the Tigers
• Whacking with a Wet Trout
• The Truth
• Unusual Requests to Wikipedia
• The Village Stocks
• The Stephen Colbert Elephant-Tripling Pandemic
• Wikipedia Widow
• What Would Jimbo Do, containing a useful photo gallery of Things Jimbo Does

And any other random selections from The Wikipedia Humour Repository, especially the many songs.

• Bad Jokes and Other Deleted Nonsense
• For an interesting peek at the past: Wikipedia Nostalgia Archive

And, on an unrelated note: Exploding Whales