I'm happy with the system I've got for coming up with NPC names on the fly, but off-hand I don't know of a good random description generator. I need that more than the names, really; my physical descriptions tend to devolve into "he has, um, brown hair," whereas with names I just start naming them after people I know.
Any of you folks know of such a thing? Double-points if it includes sci-fi compatible clothes and so on, but all I really need is a basic physical description. Clothes I can manage. ("He looks fancy.")