6. 'Lethal Weapon'
Danny Glover was just 41 when the original Lethal Weapon came out back in 1987, but he played a grizzled cop on the verge of retirement. He gets partnered with a recently widowed, suicidal young hotshot (played by Mel Gibson) that gets them into all sorts of trouble since he has absolutely no fear of death. It's a dark premise, but director Richard Donner also brought out a lot of laughs. The formula lead to three sequels, though they went pretty downhill after the stellar second one. Any talk of a fifth one ended when Mel Gibson went completely insane.