This monthly celebration in downtown Cambridge features an Art Walk with free art gallery receptions, as well as specials in the independently owned shops and great dining. Shops and galleries are open all day and into the evening, most until 8 or 9pm. The Art Walk (Dorchester Center for the Arts, Main Street Gallery, Downtown Frame of Mine) starts at 5pm. Live music is on tap at several restaurants later in the evening. As always on Second Saturday, downtown’s restaurants will be busy, so call ahead with your dining reservations. Plenty of free parking. Updated info at DowntownCambridge.org.