The wobble board is a musical instrument invented and popularized by Australian musician and artist Rolf Harris, and is featured in his best-known song "Tie Me Kangaroo Down, Sport". A wobble board, like some other musical instruments, can be ornately decorated because its large surface area can act as a canvas without detracting from its musical capability.
The instrument is played by holding the board lengthwise with the hands holding the edges and flicking the board outward, thereby making a characteristic "whoop-whoop" noise. The angle at which the board is held, and the way the board is "flicked", can alter the timbre of the sound produced. It is similar to the thunder sheet, a metal instrument used to imitate the sound of thunder in 18th century theatre.