take a big computer-game and finish it.
Rent all the movies you've always put off watching,
take up warhammer or other miniature-warfare gaming (you'll fill the whole month with that one alone)
take up climbing, playing some sport, learning to cook in a new (or your first) cuisine or expand on one you know (italian is more than just pasta & pizza, actually, it's mostly *not* those things)
take some kind of dance course,
take up massaging (can always be fun
)
Get those books you've always wanted to read
pickup some tapes or books and finally learn *insert language here*
damn, I want a whole year free, still want to do alot of stuff on that list myself