There is a gym downtown called the Pinnacle Club. I'm not sure if they offer day passes. There is also a YMCA downtown. If you want to drive a little ways to midtown (about 10 minutes), definately come to 24 hour on 76th & Cass. It is our newest 24 hour in town (opened last winter) and the nicest, IMHO. We'll be working out there on Saturday around 1p-3p (tentative). If you want more Omaha info, don't be afraid to ask!