I'll start! You should give people money for doing well in the Marble Camp, then let them buy cards. Each card has a certain effect, and the less common the card, the more powerful it is!
For example: Boring Card: Like Small Win Token, Usual Card: Like Win Token, Common Card: Like Revenge Token, Rare Card: Like Immunity Token, Impossible Card: Like Ultra Revenge Token, Master Card: Immunity Token crossed with Revenge Token, Hallelujah Card: Like Elimination Token.
No, that doesn't work. Just make one square as big as you want your outer border to be, and repeat for the inner border. Put on grid, and make their centre point the same. Then select both, conbine shapes, subtract, and you're done!