I Found this on the San Mateo Patch:
CuriOdyssey Museum, 1651 Coyote Point Dr, San Mateo, CA 94401
Next on: Today, June 5, 2011
Free admission the first Sunday of every month at Coyote Point Museum. Parking is $5.
And the park is excellent too.
Admission by car to the Park is $5, otherwise free