From Zappa Wiki Jawaka
The Monkees were an American popgroup who were popular from 1966 until the end of the sixties. They were the stars of their own surreal TV show and obviously inspired by The Beatles. They scored hits like "I'm A Believer", "(I'm Not Your) Steppin' Stone", "Daydream Believer" and "Last Train to Clarksville". The bandmembers were forced to playback their vocals and instruments, but after their third album they rebelled against their producers and managed to win their independence. After their show was cancelled in 1968 their popularity gradually sank away.
Link with Zappa
Zappa made a cameo appearance in the Monkees film Head (1968), accompanied by a talking cow.
He also appeared in The Monkees' TV series in the episode "The Monkees Blow Their Minds" (air date: March 11, 1968). There he appears in a sketch were Monkee Mike Nesmith interviews him. Zappa asks Nesmith if he can be "Mike Nesmith"? Nesmith agrees but only on the condition that he can be Zappa. In bad disguise the interview continues. A later segment shows Zappa "playing" a car by beating it into submission. This is done in a Monkees-style montage to the Zappa song "Mother People".