Definitely NBA Ballers, the solo game is fun and the multiplayer never gets old, I bring it over to friend's house's all the time to play it since I still have a copy, would be nice to have a digital one on the ps3.
Bauldur's Gate: Dark Alliance 2. That game was soooo good when I was a kid I used to play it all the time, and as a kid it was obviously a bit of a challenge to me which always makes it more fun. Was also really fun to play with my friends 2 player. I also just played it recently now a bit more grown up and found that it was really easy compared to what I remembered, and I completed the whole game in a day. :D