Like Broadway stars, the performers in this show spontaneously break into songs that you’ll continue singing all the way home. Unlike in musical theatre, however, they’re making it all up on the spot: The characters, storylines, choreography, lyrics and tunes. And they’ve done it on the iO stage more than 600 times. Opening Night Musical Has broad appeal among audiences (you’ll see fans of several generations) and also performers (the creator of Glee recently dropped in to join the cast). Reserve and arrive early.