Conversation so far:
When did Joe Raposo appear on Sesame Street?
Raposo performed several uncredited stock characters on Sesame Street during the early 1970s.
How many times did Joe Raposo appear on Sesame Street?
Why did Joe Raposo leave Sesame Street?
Joe Raposo left Sesame Street to work on the show The Electric Company.
Are there any other interesting aspects about the article about Joe Raposo?
Raposo was a close friend of Frank Sinatra, Tom Lehrer, WNYC radio personality Jonathan Schwartz, and Academy Award-winning filmmaker Bert Salzman.

Question: What did he do with cookie monster?
Self-contained rewrite: What did Joe Raposo have to do with cookie monster?