Why imagine how celebs and their friends live when you can watch Entourage and see for yourself? Based in part on executive producer Mark Wahlberg's own experience rising in the biz, Entourage follows A-lister Vincent Chase (Adrian Grenier) as he navigates his newfound fame in Hollywood while surrounding himself with a -- what else? -- entourage made up of old childhood friends. Celebs big and small are known for guest-starring as other actors or parodies of themselves.