Foster City Art & Wine Festival is a fun, famiily-friendly home-town event. Look for traditional offerings (like art and wine and entertainment, fire truck, ambulance etc.), and the kids' favorite, the popular carnival area, with rides for kid/teens/adults.
The festival is Friday, June 4th to Sunday, June 6th. The booths shut down earlier than the rides, in case you planned to do some late-night shopping.
Friday June 4 - 5 pm. to 11 p.m.
Saturday June 5 - 10 a.m. to 11 p.m.
Sunday June 6 - 10 a.m. to 5 p.m.
Parking is free at Parkside Towers (exit 92 at Foster City Blvd, and follow the signs). The festival is next to the lagoon at Leo Ryan Park (corner of E. Hillsdale and Shell Blvd.)
By the way, you can order discount tickets or wristbands for unlimited rides until 4:45 p.m. on June 4th. I highly recommend these if you're planning to come. You'll save a lot of money and the kids can go on a lot more rides with you looking like the best parent ever. Discount tickets are $20 for 30 tickets (35% savings), or unlimited one-day wristbands for $20 ($5 savings). I think the kiddie rides are around 3-4 tickets each.
Discount tickets are available at the Foster City Recreation Center, 650 Shell Blvd. Monday through Friday 8-5, or at the Foster City Chamber of Commerce, 1031 E. Hillsdale Blvd, Ste. F - 9 a.m. to 5 p.m.). Call (650) 537-7600 to get them by mail, or send a check made payable to the Foster City Chamber of Commerce, 1031 E. Hillsdale Blvd., Suite F., Foster City 94404 or send your Visa/MasterCard info and send a SASE.