I have been converted to soccer by watching and participating with my girls. I love it.
I've become a rugby fan, after watching the Wallabies (Australian rugby union team) a bit - and engaging in some banter with our old (and missing)(and missed) friend John - oldandknew, who is a great supporter of English rugby.
I'm a definite cricket fan - happy to spend hours watching, on TV, or at the grounds. And they left Brett Lee out again! Sheesh!
Watch tennis, too - and that's the only sport I play.
I was converted to snooker after playing it. Or, more correctly, trying to play it. Once I realised how hard it is to pot a 2" ball in a 2.5" pocket which is 10 feet away, and leave the cue-ball in an area of a few square inches at the other end of the table to make the next pot, then I could appreciate the game. And I love it, both playing and watching (on TV. It's not a game I'd want to watch live again).