Kiyoshi Ito (of Ito calculus fame) is dead.
(When? I'm not sure. The New York Times says Monday, the 17th, but the Japan Times published an obituary on Saturday the 15th which said he died "Monday" -- so I'm guessing the 10th.)
See the obituaries, the MacTutor biography and Wikipedia article, or this Notices article upon his receipt of the Gauss Prize for an idea of his contributions.