Room 101 was the room in George Orwell's book '1984' which contained
"the worst thing in the world". The BBC1 have taken this concept
and turned it into a TV show in which various celebrities talk about
things that they hate.
Interestingly the origins of Room 101 was at the BBC anyway. Room
101 was the room of a senior BBC programme editor who often rejected/edited
Orwell's work. Orwell took his (literary) revenge by making the
editor's room the ultimate evil place.