A sex tape featuring Johnny Carson with his wife is being shopped to private collectors. It's unclear which of Carson's four wives is in the video, which was filmed in the 1970s. The video starts with five minutes of Carson and his wife lounging in the nude by a pool. It then cuts to the bedroom, where for 20 minutes Carson and his wife deliver a performance way too hot for TV. Sources say the owner of the tape tried to sell it to the Carson estate in September. The estate reportedly balked at buying the footage, and threatened to sue if it ever saw the light of day. For legal reasons the tape can only be sold to a private collector and not a porn company.