As the piped-in strains of “Hava Nagila” fill the air, Raisman begins to tumble, flip, and soar, all while red, white, and blue spotlights dance around her. For nearly two minutes during this November show, she reprises the flawless floor routine she used to capture Olympic gold and America’s heart at the London Games. Only she’s clearly more relaxed now — as are the fans. Rather than watching nervously, they begin rhythmically clapping to the Jewish folk song, restoring its vibe, from nerve-racking competition soundtrack to kinetic wedding crowd pleaser.