Clothes Optional...

Your clothes may be optional, but great art isn't. The Leopold Art Museum in Vienna is currently offering free admission to all naked visitors (who must also be quite strapped for cash).

I visited the museum just last summer and it is terrific. Any trip to Vienna without a few days at the MuseumsQuartier is a mistake. They also have a wonderful coffee house on the roof, but when I visited I had to wear my clothes the entire time.