Well, in high school, I ended up getting pretty well addicted to Magic: the Gathering. I started looking for sites and resources to help improve my game, and eventually, I ended up being one of the best players at my school. After high school, I had a hard time finding opponents, and an even harder time keeping up with all the new expansions and whatnot - it was just too expensive. For a while, I didn't have a serious obsession. And then I picked up Pokemon Ruby.
I had played Pokemon Blue and been fairly into it, but I'd missed out on Pokemon G/S/C. Seeing all the new stuff they'd put into the game since Blue really gobsmacked me. So I went about seeing if there was a competitive group for the game, and found Smogon. ^^
Smogon has helped me - and hold on to your hats, any "PKMN is not SRS BSNS" folks who may have snuck in - to really enjoy Pokemon more than ever before. Learning new strategies, figuring out how to beat tough opponents and helping others to perfect their teams - how is that not fun? But anyway, that's my extremely long story.