What is it like behind the set of a TV series?

I have always wondered what it is like on a TV set. I wonder what it's like for the actors. Are there generally rehearsals? I know for a fact that on certain movie sets, such as Tim Burton's, there are hardly any rehearsals (E.g. Alice in Wonderland - there weren't many rehearsals). I've always wondered what it's like. I can't be too specific on what I'm really asking because I don't know too much about TV sets yet. Please help and be specific as possible :)