If you find yourself in London (especially if you are a Chelsea fan), the tour is very nice. They have an informative museum on the history of the club and the stadium, with videos of many matches, some of their trophies and a display on the evolution of their jersey. The tour itself is about an hour and ends (predictably) at the team store, which dwarfs any team shop I've seen in the US. It's pretty easy to get there via the 414 bus from Hyde Park Corner or the tube (with a short walk at the end). Arsenal has similar tours.