Swim! If you stay on the campus you will have complimentary access to numerous pools, including a very large and very nice olympic pool and a diving pool with diving boards of various heights.
Go to the waterpark known as PAO Parque Acuatico Oaxtepec. If you are staying on the campus and have an identification bracelet given to you when you check in to a hotel on the campus you will get half off of the admission price, which should come out to about 60 pesos a person. There are plenty of terrifying waterslides/toboggans, a wave pool, restraunts, and a bunch of regular pools.
Go to the club house CASA CLUB. Here, you can get on the internet, workout at the gym, go to a restraunt, order a snack like ramen noodles, or sit in a sauna...all free if you stay on the campus.
