From SFBC:
Join the SF Bicycle Coalition, parents and children as we enjoy a day in the park with fun bike-related family activities, like our Freedom from Training Wheels program and a Bike Road-eo course that teaches two-wheelers with and without training wheels basic bicycling skills. Show off your baby bike seats, trail-a-bikes, and Xtracyclies (or however your family gears up), and get advice at our Family Bicycling Showcase. Participate with your family in games, a bike parade, a scavenger hunt and more! Free! To register, go to http://sfbike.org/Family_Day.