Noun

1. a beach party in which clams and other food are cooked in a pit dug in the sand; the clams are cooked on hot stones and are covered with seaweed

Adjective

1. fig. attrib. informal, makeshift, sloppy

   not in their Ivy privilege or clambake geography — New Yorker, 9-16 August 2004

Verb

1. To smoke marijuana in an enclosed space such as a car with the windows up