If you don't celebrate Christmas and are looking for things to do over the December 24-26th time frame, here are some ideas:
CHINESE FOOD WITH THE CHARACTERS
Enjoy a Chinese food dinner and get photos with cartoon characters (and your kids) at the PJCC in Foster City.
When: December 24th, 5-6:30 p.m.
Where: Peninsula JCC (800 Foster City Blvd., Foster City)
RSVP: Preregistration required - event sells out.
CONTEMPORARY JEWISH MUSEUM
Free on Christmas Day, thanks to Target Family Fun Days. It's the only SF museum open that day. They have an awesome Curious George exhibit.
When: December 25th, 11 a.m. to 4 p.m.
Where: Contemporary Jewish Museum (736 Mission Street, between 3rd and 4th in SF)
The San Jose outdoor Downtown Ice Rink is open on Christmas from 2 p.m. until midnight. See their schedule here. The holiday rink at Union Square in San Francisco opens at 10 a.m. until 11:30 p.m. You can get advanced tickets here.
Here are some more ideas from Bay Area on the Cheap and Travel is More Fun with Kids.