The "please sb" thread back in the days of the Crap Shack/Post 9/11 World cracked me up, as well as the first Chain Game.
Also the Eastenders Crew. Shit was hilarious

And Kaibasaber, and her enormous purple text and constant re-posts of her demo of "Kindom Hearts 2", which apparently had Link recruiting Nintendo and FF characters. It was a hilariously terrible game and pretty much got her banned.
Then there was Kazeuri, who used to do hilarious news posts on the main site (silly, but hilarious) and then later got banned because he went all "FUCK GW IT IS SHIT NOW" so the admins trolled his topic by editing pics of crying babies into his rant.
Ryan's fall from power and subsequent ban.
Hundley's fake Pokey comics.
Sadly my "best" memories of this place are of pretty dumb things :P