I'm expected to organize a mud-wrestling contest. How to go about doing this?

When we suggested it we weren’t really that serious, but we picked it up anyway and are now seriously looking at organizing a mud-wrestling contest. Now I’m looking at what to think of, and I’m fully expecting Fluther to know more about it.

Currently I’m thinking we need a water supply at the location of the wrestling, and I suppose we’d best buy some mud-like substance at the garden centre (Wikipedia suggests something called Bentonite). I suppose a plastic mat would be easiest to use as floor, though perhaps a small inflatable children’s pool would be possible (financially) as well.

More things to think about:
* What rules would be best/most fun? Just draw a circle and have one push the other outside of it, and perhaps also flooring the opponent?
* Should we do a competetion/a tournament/something else?
* What else am I forgetting?

All input is appreciated.