Important fact No. 1: For the fourth year in a row, the Killers have released a single on World AIDS Day, with all digital-sale profits going to benefit the (RED) organization and the Global Fund to Fight AIDS in Africa. Important fact No. 2: The single is good! The song’s called “Happy Birthday Guadalupe,†and has Latin horns and guitar, plus a few grade-school-level Spanish lyrics sprinkled in, but for the most part that just adds to the celebratory vibe. No, it’s not actually about Christmas, but since the title lass (a “Mexican angel,†we’re told) is getting the full brunt of Brandon Flowers well-wishing, it left us feeling festive anyways. (One other thing this song is not about: Our Lady of Guadalupe, who appeared to Saint Juan Diego on the hill of Tepeyac somewhere between December 9 and December 12, 1531.) Also working in its favor is that “Guadalupe†features guest vocals from Mariachi El Bronx, the all-mariachi alter ego of L.A. punk rockers the Bronx, and though the accompanying video doesn’t have an actual appearance by the Killers, it does have Luke Perry.