Peter Jackson's King Kong - GameCube
Lego Star Wars: The Complete Saga - DS
Just the two games completed this month, one of them never played before and the other played numerous times previously.
King Kong I picked up cheap on a whim from a charity shop and turns out that it's actually quite an enjoyable game. It's an FPS game and whilst on the surface you go around blasting dinosaurs you have to be very careful with your ammo as you can find it running out quite quickly, especially with the stronger weapons. As you go through the levels there are a lot of sticks/spears and bones that can be picked up and used as weapons and you spend a lot of the game deciding when would be best to use the spears and when would be best to use ammo.
As for Lego Star Wars, this is a game that I've now completed three or four times and each time I go for 100%. I just find it really enjoyable and it's a game that can be played in short bursts so you can dedicate as much or as little time you want to completing it.