The Rock Your Sock’s Off formula is simple: you donate a pair of new or gently worn shoes for charity, and pay half the ticket price. In return, you get a night of music and the knowledge that your shoes helped someone who needed them. This year, the festival teamed up with SA Sneaks Up (which will be showcasing unique and custom made sneakers) and offers another great lineup: The Offbeats, We Leave at Midnight, Blowing Trees, The Whirlybirds, Last Nighters, Sounds Under Radio, The Lost Project, Jimmy Dasher, Elijah Zane and not one, but two nights; if you buy the first one, you can come to the second one for free, which is not a bad idea — no two shows are the same. $6-$8 (half-off if you donate a pair of shoes); 9pm Fri, Feb 8; 502 Bar, 502 Embassy Oaks, (210) 257-8125, 502bar.com. Check out our full online calendar of upcoming events here: calendar.sacurrent.com.