BOBlienation Trilogy
A three level scenario in which you're helping a mining colony's AI fend off an attack from Explodabobs. Generally, I don't like Explodabobs, but this was a playable scenario. The biggest problem was a complete lack of save terms-you have to play the entire thing in one sitting. (Luckily, it's not too big.)
Levels in map "BOBlienation Trilogy":
BOBlienation
Boblienation: Station L'wythran
BOBleination: The lunar power station