What is Knock Block?
1.
Punishment, in the form of a hunk of plastic that the band director bangs on with his conducting stick to keep time when the band keeps messing up the rhythm of a certain song. Usually makes an agonizingly sharp and loud sound, particularly for those poor suckers (like me) who are sitting in the front row of chairs.
Band director: " You guys keep screwing up this song! Joe, would you go out to my car and grab my knock block for me?"
Band members: "AAAGH! NOOOOOOOOOOO!!!"
See