Folsom Street Fair
From wipipedia.org

The Folsom Street Fair is the worlds largest leather event which takes place every September in San Francisco. It is located in San Francisco's South of Market district on Folsom Street between 7th and 12th Streets.
See Also
- Folsom Street East - a street-fair in New York, modelled on the FSF
- Kinkfest - an annual celebration of alternate sexuality in the UK