I used to be addicted to WoW and I healed myself by using the parental controls to block at one 30-minute slot every 4 hours. It was great.
I have a new game addiction now, on Steam, and it turns out Steam has no parental controls. Boo.
Here's my wishlist:
I don't want to be able to play the game between 12:30 AM and 8:30 AM.
I don't want to be able to play the game for longer than 3 hours without a short (but not too short) break.
I play single-player, so network blocking is ineffective.
I prefer if I'm able to block only the target executable, but a system-wide block is an acceptable workaround.