2 story roof. falls count anywhere. first person to get thrown off has 25 seconds to climb back on the roof or they lose. No foreign objects except one chimney tool joey will hide somewhere on his roof. That is the only outside interference to be allowed.
There will be a ladder at 2 sides of the house to make it easier for someone who gets thrown off to get back on. But let me warn yoyu. If you are thrown off and it appears you have lost, I may attempt my super frog splash off the 2nd story and if I hit it's, lights out.