Not the best, but funniest names I've seen around, off the top of my head:
Dudemandude
Blackpeople
Mexican Jew
Your mom was good last night
Your dad was good last night
And the funniest ever - General Abushaka or something like that. There used to be a faker, bison hated him, was always kicking/banning the guy for using "General Bison" name. Made me laugh so bad every time he joined and changed his name to get bison pissed lol, and bison kept changing his name using sm plug-in. For some reason plug-in was changing it to general abushaka. The guy calmed down or something, and left the name as is. So I know two generals around here, Bison and Abushaka. Please correct me if you find his name in gameme, but I'm almost sure it's abushaka. Old timers probably remember this.