Grease fans were treated to a surprise they’ll never forget when John Travolta showed up in character as Danny Zuko—leather jacket, swagger, and all. Fans at Friday night’s “Grease” sing-a-long at the ...

Add Yahoo as a preferred source to see more of our stories on Google. Summer nights are in full swing. And to kick off the season, John Travolta made a surprise appearance at a “Grease” sing-along at ...