Michael "Mike" Shapiro (born December 29, 1965 in Springfield, Massachusetts) is an American voice actor. He voices Silverado Sam and Darien in Putt-Putt Travels Through Time and Andrew Glimmer in Pajama Sam 2: Thunder and Lightning Aren't So Frightening. He's well-known for voicing as The G-Man and Barney Calhoun in the Half-Life and Portal universe Half-Life Series, and McZee McZee in 3D Movie Maker.