Article 1: The foosball table shall be kept in a state of pristine condition, except when a goal is scored.
Article 2: The committee reserves the right to modify rules at any time, without warning, to maintain the integrity of the league.
Article 3: Players are not allowed to touch the ball with anything other than the foosball stick.
Article 4: All disputes shall be settled with a game of rock-paper-scissors, played in the presence of at least two other members of the committee.
Article 5: The winner of the league shall receive the Golden Foosball Stick, a trophy of unparalleled beauty.
Clarifications of these rules may be found here and here.
For the love of all that is good and holy, do not cheat.