The term 'shell game, e.g.' is referring to a type of SCAM, which is defined as a dishonest scheme designed to cheat people out of money. The shell game is a confidence trick in which a person, often referred to as a 'MARK' or 'VICTIM', is tricked into believing they can win money by guessing which of several objects, usually shells or cups, contains a small ball. The scammer will move the shells around and the MARK must guess which one the ball is under. In reality, the scammer has control over where the ball is placed and the MARK will never win.