Answer... Not a God DA# thing!!! Go to LaCrosse if you can otherwise Hit the gym, go Running(they have a nice Gym/Indoor Pool) McCoys is the club on post, they have decent food/beer, Bowling Alley, new PX and Comissary next to it.
Theres a small Military Muesum with an Outdoor static Display near the Military Academy (ask for Directions)
Bring some fishing gear and grap a map from Range control . Couple of good fishing lakes up on north and South Post.
You did'nt say what your doin there... and if you have your own transport or not. if you have no wheels your options are limited.
Sparta and Tomah are the two closet towns about 10 miles apart from the main gate. Typical small towns with a Walmart and a grocery store and a few bars and restarants.
This time of year the post starts to get quiet as Annual training for most units is winding to a close and a lot of the business's switch to their Winter Hours which can force you to go into town.