Let's try and forget the debacle that is the mobile Dungeon Keeper that EA put out on iOS and Android. No, let's get the true original that lets you play the game rather than make you wait.
GOG has the original Dungeon Keeper for free for the next 45 hours or so. If you never experienced it, now is the time and see how Dungeon Keeper was meant to be played. It's too bad EA had to go an ruin a great franchise with the mobile version they have out now.
For a few days at least, you can find out why it's fun to be the bad guy without having to spend a dime.