If you've never played Baldurs Gate for the PS2 before you should. It was one of my favourite multiplayer games. It's quite old, but is really fun, and is as serious as the player, so if you mess around, you'll enjoy it, and if you are focused, you'll enjoy it.
It's an action RPG (loosely) for two players, and you can pick between an archer, a sorceress or a dwarf.
According to the box it is a "Tour de force" XD
You basically run around killing things, and collecting weapons and items that are dropped along the way. It's more fun with two people, and if you don't take it seriously i.e stealing the gold after the other person's killed the enemy, or while they are dropping weapons to sort out their inventory, steal them and don't give them back
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It'll keep you occupied over a holiday.
http://uk.gamespot.com/ps2/rpg/bald...vert&om_clk=gssummary&tag=summary;read-review
You should be able to find it pre-owned, but good luck in finding the sequel- it disappeared from existence were I live