Wresting in minecraft is about as basic of a mini game as you can get. The game is played by pushing your opponent out of a ring, or off of a row of blocks in the air. Hitting is usually not allowed, though it does make it a bit more interesting in many cases.
Using shift to prevent yourself from falling is not allowed.
There are a few variations which could make it a little more exciting, though they basic execution is always the same.
Lava and Soulsand
You can add lava on the edges to kill whoever loses. By making the platform out of soulsand, anybody who steps too close to the edge will automatically catch fire, so the players don’t even have to be pushed in, just pushed over the line.
This is somewhat the same as the lava version, as players will lose when they get close to the edge and take damage from the cacti. This is a good way to prevent cheating, as even sneaking won’t help you here.
If your audience gets bored, which they most likely will, allow them to throw eggs and snowballs, or perhaps even let them shoot arrows and finish both players.
South Park Style
Make it all about a story and completely ignore almost every aspect of wrestling. Dress up, create good looking set pieces and perfom for your audience. Don’t forget the rooster (they took our jobs!).