Baseball Cards - Used to be a big collector of these in 4th to 6th grade... rode my bike to the baseball card shop at the corner every few days, spent my allowance on cards and price guides, etc... still have a few cards that are worth money, sitting in my basement.
Anime - Used to attend the anime club meetings at my college, and have bought a few series that I've tried to get into... but never got around to watching them, or lost interest after a few episodes. I really like Miyazaki movies though.
Drawing - Did a LOT of sketching, usually when I was bored in class, would draw anime and skylines and even earlier when I was little, drew video game maps and came up with video game ideas based on my friends. Of course, being done with grad school leaves me with hardly any time to sit down and draw.
Game development - This is something I spent a lot of time doing, making games in ZZT and MegaZeux, 2 ANSI/textmode graphics based game creation utilities, and RPG Maker. ZZT is famous for being Tim Sweeney's (the founder of Epic and creator of the Unreal Engine), first game. I finished my magnum opus for MegaZeux a few months ago, and aside from some small stuff here and there (they have "day of Zeux" competitions twice a year, where you have a day to make a game out of either of 2 topics), I don't see myself making much in it anymore.
Reading - I was much more of an active reader when I was little, specifically fantasy genre. I read a lot of Piers Anthony, I know that is pretty LOL around here but oh well, when I was in 7th grade, it was a fun read. Lately the books I have been mostly into are alternate history fiction, nonfiction, or self-help/guide type stuff (i.e. The Game and PUA material).
I still like video games a lot though. Lately the things I've been getting more into are - hanging out and trying to meet girls, dating, mountainbiking, weightlifting/gym, spending time outdoors, and DJing.