There may be wind on Saturday which is always good.
Many people live in or near Chicago that they don't need a hotel, so it's not the best place to ask. Lots of websites out there that offer much better information about hotels then a kiteboarding website. If we lived on a small island with not much to do it would make sense for us to know, but this is one of the biggest cities in the world. Too many options to count and not one can stand out. It really depends on budget, location, view, etc. This is why you aren't getting a good response on a kiteboarding website.
Things to do. Again, HUGE city, near anything is available. http://www.tripadvisor.com/Attractions- ... inois.html
Number 2,3,4,5,8,10,14, and 17 are some of my favorites. Also try a SUP, or kayak rental on the beach or river. That is a cool way to view the city.