I uses to get into collecting Basketball cards with my neighbour next door during my childhood. Neither of watch, played, or even liked basketball, but we insisted on collecting them anyway. I grew out it by age ten though.
You just reminded me of something that most people here probably did in one way or another, card collections.
I used to collect holographic Pokemon cards. I had around 120 I think. A friend of mine had some kind of CD game that taught you how to play with them properly but honestly it was pretty stupid with all the energy cards and all.
Never really got into Digimon cards just because Pokemon was enough.
Eventually I got into playing Yu-Gi-Oh. I was pretty damn good, only one of my friends could consistently beat me. He was crazy good, he went to tournaments and would spend $50 on a single card if it was really good. Me on the other hand, I started off with one of those starter decks I think they were called and traded my way to a workable deck. I bought a few rare cards off a friend but for the most part it was down to trading for me. I still have the deck I used, I made a blog about it months ago - Link.
I miss playing Yu-Gi-Oh. I was good and it was fun, but I don't know a single person that has them anymore. It would be nice to play a game or two every week.