112°) "I've converted some rules from the Complete Book of Elves for my new character".
113°) "I've just read that DragonLance novel, and I want to play a small guy, for a change..."
114°) Your DM run a d20 Rokugan campaign, and you come up with the Dragon Star Starfarer's Handbook.
115°) Your DM run a stone-age setting, and you were looking at the DMG's futuristic weapons while choosing your equipment.
116°) "I need a bit of background for my new character. Since in D&D we have elves and dwarves instead of elfs and dwarfs, do we have smurfs or smurves in D&D ?"
117°) You ask if your wizard can have a Smurf familiar.
118°) Since your Smurf familiar was rejected, you ask for a succubus familiar.
119°) You want to play a beholder psion in a "psionics are different" world.
120°) You want to play an awakened squirrel spellfire channeler. That or a half-dragon chuul paladin.