Friday on "The Talk" John Travolta reveals what he thinks of the upcoming Grease prequel "Summer Nights." "Grease itself, no matter whether you do it in a high school production, a college production, or a TV production or the original movie, is a perfect piece of entertainment. That's what I think. If you repeat that perfect piece of entertainment you always succeed, when you go away from it, then it's a little risky," says Travolta. "But then if you are clever enough, I'd imagine you could make it work. But that's yet to be seen. How do you do that? No one can describe the magic of "Grease."