What are some fun/good co-op PS2 games?

We just recently finished playing Mortal Kombat: Shaolin Monks and have been looking for a few games to play in co op on my playstation 2. Also, we're not looking for an online game, we're looking for a game thats offline and isn't playable with two players in co-op fashion with some kind of storyline involved. Any kind of game is fine with us, but most preferably some kind of fighting game, shooting, or anything like I said before, that has a pretty good storyline behind it.