The Nobel Prize in Physics this year will go to Saul Perlmutter of UC-Berkeley, Adam Riess of the Space Telescope Science Institute at Johns Hopkins, and Brian Schmidt of the Austrialian National University for their co-discovery of the accelerating expansion of the universe caused by dark energy. Perlmutter founded the Supernova Cosmology Project, while Riess and Schmidt founded the High-Z Supernova Search Team. These two group announced in 1998 that observations of extremely distant supernovae showed that the expansion of the universe was accelerating through a still mysterious force known as dark energy.
This has to go down as one of the least surprising Nobel announcements in recent history. The discovery that 3/4 of the mass energy of the universe is in some mysterious form that behaves as a sort-of anti-gravity was a block-buster from the day it was announced. The fact that subsequent work has confirmed this discovery continues to emphasize its importance. Good call on this one, Nobel committee.