Team Fortress Classic is an amazing multiplayer/shooting game for the PC.
You can play a game with two teams where you have to capture the flag. You can play a game where you have to hunt a important person, or you can be one of the people protecting him. There are also games where both teams consist of only snipers.
You do need to have the Internet to play the game, but if you are reading this review, then you already have the Internet. This game is worth playing because once you start playing, you can pick it up really easy.
If you like team-play and shooting games this is for you.