make a ski train then get one person to try to make it between the legs off all the skiers in that train before the end of the run. they pretty much have to lie on their back to make it through and its really funny when everyone stacks. our record is a successful pass with about 7 skiers in the line.
the other thing is throw a ball between you. leave your poles at the top of the run and play football/rugby/gridiron whatever you want to call it. if you cant find a ball use a soft toy like a teddy. they always have gift shops with that sort of stuff at every resort and you can throw a teddy a seriously long way by holding one of its legs
or another variation of the ski train is just a normal train but have a few people in it riding switch and the front person calling out directions to turn