From SF Bicycle Coalition:

San Francisco hosts one of the biggest Bike to Work events in the country.
Join the fun! It’s the 21st Anniversary of San Francisco’s Bike to Work Day and we will be celebrating Bike Month all of May.
Sign up for our free newsletter
Since opponents of Prop. K can't drive on it, may as well make it into a park too
PBAC members decide they're done wasting their time with a city government that puts parking and loading above safety