I have done 3 tandems this fall, but can't do AFF until march (DZ rules). I'm in St. Louis and I have a great gym to stay in shape at, and I'm going to be able to save hella money over the winter, but what can I do in my area (no wind tunnel) to get sharp and have fun while not jumping? I'm the kind of guy who stops the microwave at 1 second just to feel like a bomb defuser.