I went to the 2008 Festa Italiana Community Street Fair in San Mateo for maybe 1hr. It was a bit tough finding parking in the public parking lots. Everyone seems to know it's FREE on Sundays & Holidays so we had to try 3 lots & finally found one spot on the 2nd Floor. Friend said the 2nd floors connect but we didn't have to drive further.
Didn't see many Italian food. Saw Dianda's Bakery, some Italian sausage stand ($5 didn't try), Toto's pizza ($3/slice) -friends tried it, they didn't comment on it.
I'd go for Japanese food in San Mateo or the many Taquerias on B Street.
Got 3 FREE pens: One from Astound cable-internet-phone. One from Italian Cemetery Inc in Colma, and one from Topix.
Saw a booth that was selling Flapping Birds, turtles, ladybugs, etc. that's a good yard decoration for $1 each. Everyone was buying. Good looking product & so Cheap.
Classic cars were fun I guess if you're into that.
Music was just ok. There's 3 stages of music. We didn't stay long enough to enjoy it.
If you live in San Mateo I'd recommend it if you like that kind of stuff, foodwise pass.