Tuesdays and Thursdays I get my cv workout in a "spinning" class. Yeah, seems like a bit of a California thing, but it's similar to a bunch of bicycle crazies, led by a marine DI, pedaling their asses off, sweating like pigs, and going exactly nowhere. It's actually a pretty good aerobic workout. (I consider anything that gets my heart rate above 150, other than sex - of which I see damn little - as a pretty good workout.) In case you're wondering, the silhouette in the background is the marine DI leading the group in post-sadistic toe touching.
Other candidates for today (also from spinning class):
http://www.pbase.com/image/35646885
http://www.pbase.com/image/35646884
PS - Crop. Levels adjustment. Select and copy foreground to new layer and USM. Reduce Brightness and Contrast of background.