I saw Pirate Radio last week and I liked it so much, I figure that it is worth mentioning here.
The movie is loosely based on the true story of the pirate radio stations that were popular in Britain in the 1960's. The cast is full of great actors including Philip Seymore Hoffman, Bill Nighy and the guy who was Hugh Grant's flatmate in Knotting Hill.
It is hard to say if the movie is a comedy or something closer to a romantic comedy because there are lots of scenes that are both funny and touching at the same time. In the movie, a boat is stationed off the shore of England and inhabited by a crew of radio djs and station personnel. Each of them as crazy and wacky as the next.
Of course the music is also great... you have The Rolling Stones, The Who and just about every other major song of that era included in the soundtrack.
A definite must see.