Co-op Splinter Cell with my brother for 3 days straight. He is crazy. But it was fun. He likes to play on Realistic Mode, but he also likes to run out and get shot a lot. So between my 'camping' and him getting all 'leroy jenkins', we didn't get very far. We did get through all of 'Hunter sections'. But the actually missions were pretty bad.
We just have 2 different playing styles and they didn't match up to make it past 'Level 6'. Still it was nice to play together, and I think we unlocked a badge or two.