I chanced upon a rather cool project called the Uncyclopedia:
Uncyclopedia is an encyclopedia full of misinformation and utter lies. It's sort of like Congress or Parliament. Unlike Congress or Parliament, however, we do have a sense of humor. Nonetheless, this is one of the only factual pages, before everything turns into a puddle of utter confusion and disarray. Savor it. And for the love of Sophia, we know you like disarray, but stop adding confusion to this page to spite the bowel movement.
The site's done 3500+ articles in just two months - quite an acheivement. I enjoyed all the articles I read, however. I see a problem with the aim of the project: to be completely untrue. The problem with lies is that when you couple a lie with another, it has to fit in perfectly, otherwise a contradiction may arise, invalidating both the statements. For example, "Pigs can fly" and "Flying objects cannot start with the letter P" contradict each other; hence while they are perfect lies in themselves, they cease to be valid when the two are put together.
Hence, when you write out an entire encyclopedia of lies, you have to take great care to maintain consistency. This is a difficult thing to do; just to check for holistic validity is an O(nn-1) algorithm [email me if you want to know the proof to this]. (I shudder to think about the solution to the validity resolution problem).
In other words, the Wikipedia project has a distinct advantage over Uncyclopedia - it has a cool "cheat-sheet" to look up - called Reality. For ensuring consitency in the Wikipedia, all you do is check if it's really real. For ensuring consistency in the Uncyclopedia, you'll have to check with every article in the collection iteratively to make sure if your Lie is still intact.
Also, if the Uncyclopedia folks can come up with a decent consistent subset of the Wikipedia dataset, they'd actually end up creating a viable parallel universe!