The Magic Christian (1969)

Sir Guy Grand (Peter Sellers) adopts homeless bum Youngman (Sir Ringo Starr) to be heir to his obscene wealth, and immediately begins bringing him into the intricacies of the family business, which is to prey upon people's greed by use of the vast holdings of the Grand empire. They leave no stone unturned as sporting events, restaurants, art galleries, and traditional pheasant hunts turn into lurid displays of bad manners and profiteering. Things climax at the social event of the season, the inaugural voyage of the new pleasure cruiser, "The Magic Christian".