What happens when two miserable working stiffs plug into the rockin’ soundtrack of their interior lives? In the case of Rock Out—an episodic, dialogue-free “play with music” by actor Gregory Jones—you get an irresistibly cute, surprisingly uplifting Fringe production, in a bite-size half-hour. Gary (Jones), bored out of his gourd, downloads some Led Zep to his office computer, unleashes heavy air guitar, grabs up the mouse like a mic, and discovers his inner Robert Plant. His dour boss, Mary (the play’s choreographer, Tiffany Hodges), stumbles upon this unbridled display, to the embarrassment of both. But she’s repressing a shadow self of her own, one full of rage and animalistic longing. These characters are drawn and their story told through wonderful body language, facial expressions, and free-form boogie. Song lyrics cleverly advance the piece and tickle the audience. Jones (an everyman sort) and Hodges (beautiful in an accessible way) make appealing leads, and we can easily identify with their self-doubt, passion, and musical tastes. Clearly these two lonely hearts belong together, and that’s why God made iPods.