  We propose a set of devices of simple geometrical design which may exhibit a
permanent rotation due to quantum (vacuum) fluctuations. These objects - which
have no moving parts - impose certain boundary conditions on quantum
fluctuations thus affecting their vacuum energy similarly to the standard
Casimir effect. The boundary conditions are chosen in such a way that the
vacuum energy for a static device is larger compared to the energy of the
vacuum fluctuations in a state when the device rotates about a certain axis.
The optimal frequency of rotation is determined by geometry and moment of
inertia of the device. We illustrate our ideas in a vacuum of a massless scalar
field theory using simplest Dirichlet-type boundary conditions. We also propose
an experimental setup to verify the existence of the rotational vacuum effect.
