Hiller Aviation Museum Great for children and adults. Located adjacent to the San Carlos Municipal Airport. Although it is commonly thought that the airport takes its IATA code "SQL" from the nearby headquarters of Oracle, in fact, the airport and its IATA code long pre-dated the arrival of Oracle in the community.
Downtown San Carlos (five blocks of Laurel St from San Carlos Ave south to Brittan Ave) is one of the nicer small downtown streets on the Peninsula and has a nice selection of shops, boutiques, and restaurants, mostly fairly upscale but not nearly as chichi as you'd find in Palo Alto.
Jersey Joe's Hoagies, 21 El Camino Real, +1 650 592-7317. A local institution.
Harmony Yogurt, 1226 Arroyo Ave, ☎ +1-650-596-8500 (fax: +1-650-596-2958), . Sun–Wed: 11AM–9PM; Thu–Sat 11AM–10PM. A small salon that serves organic frozen yogurt, with various fruit and candy toppings, or whipped into fruit-flavored smoothies. The yogurt is made in-house, and has a wonderful smooth taste which is a cut above normal frozen yogurt. Friendly service. Good for a dessert or snack.$3-5/cup. edit
The Refuge Pastrami- Wine Pub - Charcuterie, 963 Laurel Street, 1-650-598-9813. Tues-Thurs: 11:30am-2:30pm & 5:30pm-9:00pm; Friday: 11:30am-2:30pm & 5:30pm-10:00pm; Sat: 12:00pm-10:00pm. A casual and friendly environment with fantastic food. The pastrami sandwich and hamburgers are a must order along with any of the Belgium beers on tap.
Speederia 711 Laurel Street, 650-591-9115. Quite possibly the only authentic New York style pizza restaurant on the Peninsula; serves slices and whole pies - $6 "special" for two slices and a drink (fountain soda or bottled water.) Cash only, very limited seating, although there are some city benches nearby if the restaurant's own seating is full.