‘A Life in the Theater’

David Mamet ventures away from the theater in a 1993 adaptation by the playwright for cable’s TNT. Some of the changes enrich the play; another one simply prolongs it. But Mamet’s taut look at the bittersweet bond between an aging actor and his young colleague remains as funny and as tender as ever, thanks to triumphant performances by Jack Lemmon (left) and Matthew Broderick (right). This is one of Lemmon’s finest hours (KTLA Saturday at 11:30 p.m.).