Uplink, Defcon, Darwinia, Flotilla and Atom Zombie Smasher (or basically anything from Blendo and Introversion)
Uplink is a really cute and addictive app-based hacking simulation, that sees you caught up in a dangerous mystery.
Defcon is a really cute strategy game that puts you in charge of your geopolitical "spheres" thermonuclear holocaust during WW3. Best in multiplayer.
Darwinia is (surprise!) a really cute game that has you controlling little soldiers tactically, to eradicate a virus ravaging a program populated by sentient little AI people
Flotilla is an awesome mix of Homeworld and Combat Mission, with Blendos trademark screwball humor, and a roguelike campaign mode
Atom Zombie Smasher is a little game about overseeing the evacuation of people and eradicating zombies from an urban environment using different styles of units. It's like an active tower defence game, also with lots of screwball humor