Pro Evolution Soccer 6 (or 2008 when its out) lets you and a friend play on the same team (may let more than two, I don't know).
The multiplayer is second to none for all round fun and playability (as we're leaving the house to go out in town, there's always time for a quick game of proev
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It's amazing how much fun it is. The only game I ever play, and the same goes for all my friends, is pro evo.