Ultrafast Rotation of Ultracold Gases Erich Mueller Ohio State University Great excitement has been generated by the intricate quantum many-body states which can now be probed in ultracold gas experiments. As an illustration of this trend, I will discuss the behavior of a rotating gas of bosonic atoms. Experiments in this area have already observed dramatic phenomena, including the apparent dynamical "melting" of vortex lattices into sheets. Future experiments, at higher rotation speeds, are expected to see a quantum phase transition where the vortex lattice melts into a "quantum Hall" liquid. When the gas has internal degrees of freedom, these phenomena become even richer, resulting in a range of spin textures and novel many-body properties. I will present an elementary overview of this area, and try to convey the enthusiasm felt by those in the cold gas community.