These were the closing words after each episode of the TV show Cheers. You would hear, "Sit, Ubu, sit. Good dog." Then a dog would bark.
This is the production company's 'signature' or 'vanity card' for their shows. (They are called 'badges' in the UK) The Ubu in this one is the producer Gary David Goldberg's dog, who has given the company its name: UBU Productions. It's cheesy and a little cute, which reflects the flavor of their shows.
You might have the following ingrained in your mind: the 'shh' as curtains fall at the end of the Simpsons, the typist pulling the page from the typewriter so it flies towards you and becomes a large C at the end of Knight Rider, the old lady in a rocking chair falling over after King of the Hill, the "i made this!' kid's voice at the end of x-files, and the Mutant Enemy 'Grr! Arg!' at the end of Buffy.
for the reminder of the low tech buffy signature. If you would like to be reminded of several other signatures or vanity cards visit http://www.angelfire.com/tv2/closinglogo/vanity.htm
where you will learn that the picture of Ubu with a frisbee in its mouth may have been taken somewhere in France
June, 2004: or, you used to learn that such a thing may be. Trust me.