Holiday Tree-Lighting Ceremony, 6-8 p.m. at Veterans Community Plaza, State and Main streets in downtown Los Altos. Information: downtownlosaltos.org.
Los Altos and Los Altos Hills Joint Community Volunteer Service Awards Luncheon, 11:45 a.m. at the Crowne Plaza Hotel, 4290 El Camino Real, Palo Alto. Information: jointvolunteerawards.com.
Los Altos History Museum’s 32nd (and final) annual Crab Feed fundraiser, 6-10 p.m. at St. William Parish Hall, Los Altos. Tickets go on sale Dec. 4. Information: 948-9427.