Every year, a couple thousand naked people cruise the streets of Chicago on bikes as part of the World Naked Bike Ride.
An effort to promote cycling, The World Naked Bike ride happens in cities across the world. It is, just as it sounds, a naked bike ride and has been happening since 2004.
According to wordnakedbikeride.org:
In the beginning of WNBR, the message was balancing protesting against oil dependency and celebrating the power and individuality of the human body. In 2006, there was a shift towards simplifying the message and focusing on cycling advocacy. While the ride does include and appeal to participants from social nudity circles, the rides is not focused on promoting social nudity directly as much as cycling.
This clothing-optional event is planned to start at 6pm this Saturday, June 13. The route has not yet been announced. For more information, visit http://chicagonakedride.org/.