Very rare, but sometimes something just hits the spot and the giggling commences. Here's 5 reads I can think of on the internet in this category (mostly NSFW by the way):

1. Bash.org's top IRC transcripts.
2. Planet Fargo's SWG bot transcript.
3. TV Go Home - Radio Times parodies.
4. Chuck Norris facts.
5. The very secret diaries of LOTR.

Wait, that Chuck Norris one's a bit obvious, how about Uncyclopedia's history of WWII instead? Bit geeky I guess, but that's the internet for you :-P