All these funny, punny knock-knocks have a twist: they play games with names to create big belly laughs for kids. Some are just out of this world: Knock-knock, Who's there? Martins, Martins who? Martins from outer space, Others stretch out the fun in a series of jokes: Knock-knock, Who's there? Boyce, Boyce who? Boyce will be Boyce, Knock-knock, Who's there? Gail, Gail who? And Gails will be Gails, What irresistible amusement for young comedians