South Florida alt-rock station 104.3 the Shark wants you to dig its Undertow Jam, the inaugural rock festival visiting Revolution Live (100 SW Third Ave., Fort Lauderdale) on Sunday. The concert brings headliner Young the Giant, the Irvine, Calif. rockers on tour supporting their forthcoming third album, “Home of the Strange,” out Aug. 12. Young the Giant (“My Body,” “Cough Syrup,” “Apartment”) will be joined by New York rockers Joywave, Brooklyn post-punk quartet Bear Hands and Detroit indie-pop act JR JR. The festival, which kicks off at 2 p.m., is sold out, but resales are available via Ticketmaster.com. 954-449-1025 or JoinTheRevolution.net.