Not sure if the full game is worth the $40 or $50, but the demo for Evil Genius is a blast.
The idea here is that you play a James Bond-style mastermind which entails building a secret lair, recruiting minions, training the minions for missions, and, ultimately, preparing some sort of doomsday device.
The reviews have been sort of mixed, and the demo reveals some of the games weak points so you can judge for yourself, but to me the gameplay was more than good enough give the amusing take on a wonderful game premise. I really loved watching my minions taking out the good guy commandos, but your mileage may vary.