Though Matthew and the Arrogant Sea claim Denton as their hometown on their MySpace page, they are listed as from Azle on SXSW’s web site, which means they’re from the 817, which means they’re part of the huge 817 presence at South-by. Another 817-related band, the heavily experimental Zanzibar Snails, will also be playing the festival: throughout the day/evening on Friday at Hot Mama’s Espresso (2401 E. 6th St., 512-476-6262), where the Snails will be serving as the house band-slash-resident DJ of sorts, and tomorrow night (Thursday) at 10 p.m. at Cherrywood Coffeehouse (1400 E. 38th St., 512-538-1991), where they will be joined by 817’s rowdy Mount Righteous and Fort Worth Southern-Gothic singer-songwriter Clint Niosi.