We already know there's no beating a free outdoor workout at Red Rocks—so why not sweat it out with a few thousand fellow fitness buffs? Booming beats set the stage for a variety of classes: total body boot camp, yoga, zumba, and turbo kick. Have your workout help others by donating to wildfire firefighters and victims as well as the Mile High Down Syndrome Association. Tip: All participants must register online. Sat 8 a.m.