I decided to put the rules in the comments
Rules: Marble race to the finish (the bottom of the course). The last marble to finish puts his/her team in danger. Then only that team would race and the last marble to finish that round is eliminated.
Rules: Marbles go through this marble race. The last one to finish puts his/her team in danger. That marble's team does the course again and the last one to finish that round is eliminated
Rules: Marbles go through an obstacle course trying to avoid the traps. The last marble standing wins his/her team immunity and they are taken out of the game. The next round we do the same thing. The last one standing wins his/her team immunity. We keep doing this until there is only one team left. Then the first one to fall is eliminated.