The most surprising discovery in cosmology since Edwin Hubble observed the expansion of the Universe isthat the rate of this expansion is accelerating. This either signals that a mysterious Dark Energy dominatesthe energy density of the Universe, or that our understanding of gravity on large scales is incorrect. The Canadian Hydrogen Intensity Mapping Experiment (CHIME) will produce the largest volume astronomical survey to date, potentially unlocking the mysteries the dark-energy driven expansion history of the Universe. The CHIME telescope forms an image of the entire over-head sky each night by digitally processing the information received on a compact array of 2500 radio receivers. Unlike traditional telescopes that mechanically point and observe a small region of the sky, CHIME is able to observe the entire overhead sky without any moving parts by decoding the information received by the stationary radio receiver array. We are currently building a pathfinder version of CHIME. I’ll describe the CHIME concept and its science potential.