If you are planning to stick around town for the winter break, it's not too late to sign up for camps. Here's a list of low cost options, most of which are offered through the SF Recreation and Parks Department.
Acrosports Bernal Heights Playground and Recreation Center Chinatown YMCA Circus Center City College of San Francisco Rams Basketball Camp Eliot Smith's Tiger Basketball Camps Embarcadero YMCA Glen Canyon Park and Playground Golden Gate Park Tennis Program Habitot Children's Museum Helen Wills Playground Joseph Lee Recreation Center Moscone Recreation Center Randall Museum Richmond Recreation Center St. Mary's Playground and Recreation Center Stonestown Family YMCA