Philosophy (particularly Ethics, Theories of Justice, but I enjoy all manner of Philosophical thought and debate)
Writing (I love to read, as well - pretty much anything I can get my hands on, but I am a big S/F-Fantasy guy (love Dick and Gibson)
RPGs (have played/GMed (in no particular order - AD&D, Marvel Super Heroes, Boot Hill, Gamma World, Phoenix Command, Vampire (as well as Dark Ages), Werewolf, Changeling, Mage, Wraith, Shadowrun, Earthdawn, Battletech, Mechwarrior, Star Wars (WEG and D20), TMNT - I could keep adding to the list forever. I also tinker with systems, and one of these days I'll actual finish one of the games I design)
Technology (if it's cutting edge, I like it)
Mathematics (have a math brain - it's a curse)
Bad Movies (if it was made in the '80's, I've probably seen it)
Sport (yeah, I know)
And a ton of other stuff that I can't recall right now...