For the next day and a half, the original 1997 masterpiece Dungeon Keeper is FREE on Good Old Games! You play the role of an evil demon overlord. Build you dungeon, recruit, train, and pay your minions to fight for your cause, and when you are ready, go in for the attack! Slay those who are righteous as you take over the realms of good knights and kings, laying waste to the land and making it a hell spawns paradise.

It really is a fantastic game. I grew up playing this. And now that its free for today, I can help pass it along!

http://www.gog.com/