Renowned director John Landis offers up a portrait of legendary comedian Don Rickles (in an Emmy-winning role) by blending clips of Rickles's appearances at the Dean Martin celebrity roasts and on "The Tonight Show" with footage from his stand-up routine and interviews. A slew of celebrities -- including Martin Scorsese, Christopher Guest, Robin Williams, Sarah Silverman, Sidney Poitier and Clint Eastwood -- offer their insights on the man known as "Mr. Warmth."