Bike month is May, 2011
Previous events: May 17-21, 2010, May 11-15, 2009
From the website:
California Bike Commute is a project of the California Bicycle Coalition-a non profit organization that advocates increased bicycle use, access, safety, and education, by promoting the bicycle as an everyday means of transportation and recreation.
Various special activities have been organized locally by ride share agencies, cities, counties, employers, bicycle advocacy groups, bike shops and others who support bicycle transportation in California's communities.
Events may be planned in your area, including bike tune-up clinics, morning "buddy rides," pit stops, energizing stations and noon-time rallies. Click on Local Events to find out what's happening in your area.
Visit the Smart Traveler website for further tips on commuting; a great source of transportation systems and related links in California sponsored by Cal Trans.