Warcraft 2. When I was in grade 7 I remember laughing at one of the heroes that, after clicking on him about 20 times, would say, "Stop that inceasant clicking". I found that rather amusing.
Other than that no games have really been that funny. Conkey wasn't funy to me. it was jsut crude for the sake of being crude.
Oh! I liked that line from Destroy all Humans where the main guy is instructed to talk to some cows and he says, "You want me to converse with those bloated bovine gas bags over there? But they're covered in NIPPLES!"