In any game like Link to the Past or Pokemon, I name my guy "...hahaha...", so upon introduction to allies, you will say "Hi, my name is ...hahaha..." and they'll be like "WTF his name and y he think joke now?" Yay for bad grammaer
I've used this name when I was a kid: Thepoopometer. "oopometer" stands for a thermometer that measures the density of any players poop. I was a kid, give me a break.
I have seen: Cream3142 (Tip: 3.142 is something in mathematics)
In case you're wondering, that's Pi. The funniest name I've seen is actually Team Fortress 2 Bot name (totally not a bot). Oh, and there was one player on TF2 who's username was "a stupid person". No joke.