If you come to Portland, Oregon, we have an annual Naked Bike Ride. Over 10,000 riders with no clothes (men and women) ride their bicycles through the heart of the city. It is amazing to see:
http://pdxwnbr.org/ Here is a video about it:
Several of my good friends participated last year and said it was the most fun they ever had.
I will be participating this year on June 7, unless I am already on my way to Thailand.