The old HL2 multiplayer mod Fistful of Frags is now a standalone Source game which is available for free on Steam. It is an Old West first person multiplayer team shooter where you capture objectives, (loot chests), and gain notoriety to buy weapons and accessories. Notoriety is also gained by attacking the enemy who are collecting loot or players protecting the player collecting loot. You also gain notoriety by protecting your team mate collecting loot.
More info about the game is available in the following link. http://www.fistful-of-frags.com/index.php