Personally, I have always been a huge NASCAR fan. My walls and shelves are littered with model cars, posters, and die-casts. Other than that I like football (go Panthers) and women's tennis (Maria Sharapova is a total babe). Yours?
Watching sports is boring, but I like playing baseball, basketball, football, and anything to do with water.
Watching football (soccer for the Americans.). As a hobby? Shooting no doubt, it's difficult to get into shooting in this country, but I love it! As for a more active sport? Athletics, I love 100m sprint 200m sprint, 400m sprint, long jump, high jump, triple jump, hurdles, everything. My day is not complete before I've done a little running or a little jog. I also like swimming, and I'm quite good at it, not really something I do often though.
I know this isn't really a sport but other than all the sports I already listed I like to swim in my pool every Summer.