I remember a post earlier in this newsgroup about our favorite "walk-on" characters... my vote earlier was for "bookman" but i've since reconsidered after seeing "the pez dispenser" in syndication.
the best "one-time-only" character has got to be the polar bear guy that amuses elaine with his story about kangaroo pouch envy... "i don't have to carry things too?... at least give me a pocket". He was the most adorable old man w/ the greatest queens/jewish accent. "what.. you don't want to be a polar bear anymore??"
hee hee -Jamie