This BFI release, to mark Jack Nicholson's 80th birthday on September 22nd, is on an extended run from April 14th. Full details here.
Chicago Reader review:
This slick and entertaining 1975 film of Ken Kesey's cult novel will inevitably disappoint admirers of director Miloš Forman's earlier work. Jack Nicholson plays McMurphy as if he were born to it, and the supporting cast provides fine, detailed performances. But there is little of Forman's real personality in the film, which smooths over the complexities of his Czechoslovakian work in favor of some mighty simpleminded conceptions of Life, Liberty, and the Pursuit of Happiness. With Louise Fletcher, William Redfield, Michael Berryman, Scatman Crothers, and Sidney Lassick.
Here (and above) is the new trailer.