A very simple yet lethal move relatively common in football (soccer), especially in the professional and international arenas. It involves merely letting a pass go through your spread legs to another player on your team. It takes an immense amount of coordination and trust between teammates, especially if done without verbal communication because the player initiating the move will often not be able to see the player coming from behind. This may sound stupid, but I will provide you with some examples of why, and how this move proves so effective.
Say for example, you have player A from the "Blue" team making a run down the center of the field on your defensive half of the field, and you (as a "Red" player) have the honor of guarding him, but are still at least a few yards away. Player B from the Blue team is running down the sideline, and makes a pass to player A. Using the famous defensive maxim "Fast Approach, Slow Arrival" you sprint towards the player. He moves his foot out as if to trap the ball, and so you slow down to "jockey" him. (Jockeying is where you stand in front of a player and mimic his every movement so that he cannot get past you.) He moves his foot out just a little bit more, and while you are slowing down, the ball goes through his legs to...Player C from the Blue team who just appeared from the other sideline. Now you have completely decelerated and cannot catch player C. Even the Red player who was marking C was caught totally off guard even if he was in step with him, and so C makes his/her run to the net and possibly scores.
Another highly effective (and common) use of the move can occur anywhere on the field but is most often seen done at the top of the 18-yard box. Player A from the Blue team is standing at the top of the "18" and you (still playing for Red as your trade to Manchester United fell through) are once again marking him/her, only this time you are right on top of them. Player B from Blue makes a cross on the ground that is directed towards player A and you are between them and the goal waiting to prevent a turn and a shot. A turns his/her hips as if to shoot...and once again lets the ball roll through to player C who now cracks a shot straight at the unprepared goal keeper (who is set to block a shot up the middle, not from the side.) In a game often determined by 1 or 2 goals, this move can often be the difference between a win, loss, or draw.