IceCube is the world's largest high energy neutrino telescope.  Now three quarters complete, the detector will instrument a cubic kilometer of Antarctic ice as a Cherenkov medium for the detection of astrophysical and atmospheric neutrinos.  We will present observations of atmospheric neutrinos, the results of searches for neutrinos from astrophysical objects such as active galactic nuclei and gamma ray bursts, and world-leading constraints on the spin-dependent dark matter scattering cross section.  We will also discuss the new Deep Core extension of IceCube and its potential for neutrino physics and searches for dark matter.