  Ultracold molecules represent a fascinating research frontier in physics and
chemistry, but it has proven challenging to prepare dense samples at low
velocities. Here we present a solution to this goal by a non-conventional
approach dubbed cryofuge. It employs centrifugal force to bring cryogenically
cooled molecules to kinetic energies below $1\,$K$\times k_B$ in the laboratory
frame, with corresponding fluxes exceeding $10^{10}$/s at velocities below
$20\,$m/s. By attaining densities higher than $10^9$/cm$^3$ and interaction
times longer than $25\,$ms in samples of fluoromethane as well as deuterated
ammonia, we observe cold dipolar collisions between molecules and determine
their collision cross sections.
