What is the 80's kid's show that ended with the actors opening windows and

[Business]

telling jokes? The actors were all behind a huge cardboard wall with fake windows...they would open them and tell jokes...does anyone remember the name of that tv show?
Unfortunately it is not "You can't do that on Television" it was probably a PBS show, not on cable

 

[potsie]

If they popped out of school lockers while telling the jokes it was Nickelodeon's "you can't do that on television"

 

[3Guesses]

You can't do that on TV
http://www.youtube.com/results?search_query=you+can%27t+do+that+on+television&aq=0&oq=you+can%27t+do+that+