From The Hitchhiker's Guide To The Galaxy
A full set of rules is so massively complicated that the only time they were all bound together in a single volume, they underwent gravitational collapse and became a Black Hole.
A brief summary, however, is as follows:
Grow at least three extra legs. You won't need them, but it keeps the crowd amused.
Find one good Brockian Ultra-Cricket player. Clone him off a few times. This saves an enormous amount of team selection and training.
Put your team and the opposing team in a large field and build a high wall around them.
The reason for this is that, though the game is a major spectator sport, the frustration experienced by the audience at not actually being able to see what's going on leads them to imagine that it's a lot more exciting than it really is. A crowd that has just watched a rather hum-drum game experiences far less life-affirmation than a crowd that believes it's just missed the most dramatic event in sporting history.
Throw lots of assorted items of sporting equipment over the wall for the players. Anything will do - cricket bats, basecube bats, tennis guns, skis, anything you can get a good swing with.
The players should now lay about themselves for all they are worth with whatever they find to hand. Whenever a player scores a 'hit' on another player, he should immediately run away and apologize from a safe distance. Apologies should be concise, sincere and, for maximum points, delivered through a megaphone.
The winning team shall be the first team that wins.