Let's see, when my cousin first introduced me to AD&D, he insisted on using a character named Biggus Dickus.
I once played in a campaign with a guy who had a half-ogre fighter named Stomper Door-Opener.
My son ran a gnome thief named Jonik, who for some reason or another ended up being called "Big Daddy J."
He also had a fighter/rogue named Aurelion, who was nicknamed "Pee-Break" after he got separated from the party by a summon insect swarm. By the time he made it back, the rest of the party had already taken down the enemies, and they asked him if he was off taking a pee break while they did all the fighting. The name stuck.
My brother Joseph was DMing for one of his friends in a solo game, and the guy insisted that Joseph provide him with an assassin NPC and a cleric NPC. So Joseph said, "Fine: You meet up with two guys who want to hire on. One's an assassin, and one's a cleric. Their names are Findor and Keepor." And sure enough, Findor and Keepor kept every single bit of treasure that the party encountered from that point on.