Also, Chicago is the Windy City, and the Hyatt's right on the river, which means it can be breezy. Bring business cards or something you can give new friends when you meet them. Bring a little notebook to write down addresses of your new friends who didn't bring their cards. Get 5 hours sleep and two meals a day. Smart-alecks say that you can reverse the two, but they are wrong.
More sleep is better, of course.
Furthermore, make sure that one of those meals is substantial. Hotel breakfast buffets are great for this. Loaded with energy rich fats and carbos, yes. You will be running at top speed for 5 days-this is not the time to skimp on fuel. In a five day convention, you should get away from it all for about 10 hours total.