I'd think sidesaddle would screw up your balance. Softer things sound like a winner.
Well, Grifball's pretty easy. Four guys on a team. Everyone has an energy sword, and a big.. really big.. gravity hammer. Both of these are made to kill on first strike, but usually your armor keeps you pretty safe. Only one or two people die per tournament, so it's relatively safe.
A bomb is placed into the middle of the court. The object is to get the bomb and run with it to the opposite team's goal line, where your three team mates will try to protect you, while the four people on the opposite team try to kill you. If you make it across the line, you drop the bomb and run. The bomb explodes, you get a point.
You play best of three.
Sometimes the court gets a little slick, blood and all, but it hoses down easy.