Robin Williams: amazing improv

WENN has an article about the genius of Robin Williams:

Robin Williams (photo, as Mork) saved the worst Happy Days script ever, and turned the episode into one of the beloved comedy show's best. The late funnyman was a little-known stand-up comedian when Happy Days regular Al Molinaro put his name forward to play the alien, Mork, after another actor dropped out at the last minute. Anson Williams, who played Potsie on the show, recalls that: "It was the worst script in the history of Happy Days, and the guest actor quit on Wednesday... I didn't blame him. Thursday we had camera blocking day, and Friday we're shooting it, and there's no Mork. Happy Days creator Garry Marshall comes down to the set and said: 'Does anyone know anybody funny?' And Al Molinaro raises his hand and says: 'Yeah, there's this really funny guy at my Harvey Lembeck improv class...' The next day I walk in and every writer's there. Director Jerry Paris runs up and says: 'He's a genius!' And there's Robin Williams, and I'm watching this magic man make up the whole thing and, by Friday night, it was the best show in the history of Happy Days."
Williams was such a hit as Mork that he landed a spin-off show, Mork & Mindy, which turned him into an overnight sensation.

Rico says that nothing could truly save Happy Days, one of the worst television shows ever... (Possibly exceeded only by Mork & Mindy.)