The BarrowDowns (chatroom), Svenska Hogwarts (Swedish site, not there as much as of late), Neopets (when the mood strikes to play some silly games, I don't usually participate in the community), NaNoWriMo (I love their forums! So much information gathered there... man.), April Fools (Like NaNo, only smaller and less stressful) and The Spork Room (which used to be a subsection of the latter two, but is now it's own thing).
I also spend most my time on IRC, and play various internet games.