Oysters are in Season feautures the improvised humor of Swede Sorenson, Dean Preece and Molly Parkin as they play out sharply satiric situations. Utter foolishness abounds in short skits that range from an employment interview with an applicant whose previous experience has left him physically uncontrollable, and an unsuspecting golfer who arrives for a first lesson, to scenes of mayhem with a hammock and a chinese lantern masquerading as an artificial kidney.