When a Helmholtz resonator is driven with sufficiently high amplitude, the pressure difference between the inside and outside of the resonator and the non-uniform oscillating flow of air into and out of the resonator opening results in a reaction force on the resonator akin to rocket thrust. The earliest demonstration of “acoustic repulsion” using small Helmholtz resonators was reported by M. Dvorak [Philos. Mag. Ser. 56(36), 225 (1878)]. Lord Rayleigh explained that the average pressure inside the resonator is higher than the external atmospheric pressure, with the result that the “resonator tends to move as if impelled by a force” [Philos. Mag. Ser. 56(37), 270 (1878)]. This demonstration will show an updated version of Dvorak's 1878 apparatus using Christmas ornament balls as suggested by Uno Ingard, [Notes on Acoustics (Infinity Science Press, 2008), p. 336]. In addition to showing the resonator rocket in action and discussing its history and various theorical explanations, this demonstration will show how the amount of “thrust” may be measured with a mass balance and will attempt to visualize the flow in the neck of the oscillator.