You see celebrities like Jennifer Aniston on them all the time and now you'll know why.  Stand-up paddleboarding (SUP) is a low-impact all over workout that torches more than 400 calories an hour!  Plus, you can do it in your swimsuit and get a tan all at the same time.  You can even do it right here in Oklahoma!  Just head down to Riversport Adventures on the Oklahoma River and you can rent them by the hour for only $15.  If you get really good you can try SUP Yoga!