A couple of days ago, on a whim, I bought the Father Ted box set. That was definitely a good idea. Watching the episodes has cheered me enormously.
Fantastic fun - I have the episode "The Plague" playing at the moment. There are only about four or five situation comedy series I have really liked.
Blackadder is one of course, Fawlty Towers another. Red Dwarf I found fantastic, if I don't think about the last couple of episodes and the recent re-union thing.
I like Monty Python, the Fast Show and some other comedy sketch series but I generally find sit-coms annoying. But Father Ted is something rather special.