Reading, hiking. In college I tried poetry (which was predictably atrocious), but writing even bad poetry gives you a better appreciation for reading good poetry.
I have a tin whistle, but I broke the fipple and never replaced it. I keep thinking I should switch to harmonica.
I'd like to try my hand at gardening, but I live in an apartment. My friend is buying a house--I'm gonna beg and plead come spring for her to set aside a little patch for me to play around in, since it's only a few blocks from my apartment.
Car maintenence (97 Jeep Grand Cherokee) is more a duty than a hobby, but more and more I'm finding that I approach it with relish, and finish it with great satisfaction. Robert Pirsig and my Haynes manual to the rescue!
I've also tried brewing mead (terrible!), learning a second language (failed!), drawing (decent-but-not-great), painting (worse than drawing!), and calligraphy (I could get good at this if I worked at it).
Every once in a while I get really into Buddhism--so naturally, I shave my head, set aside time for meditating, and generally become a better person/co-worker/brother/son/friend for a few weeks (but seldom longer!)
Never stop learning, teaching, playing, exploring, experiencing, and living!