Like metal, ska is a genre that just refuses to die. The Jamaican-born music began cross-pollinating island rhythms with the sounds of American jazz, R&B and soul in the early 1960s, eventually giving rise to reggae, and averages at least one revival every decade via groups like the Specials, English Beat, Sublime and No Doubt. Some musical prognosticators believe another one is just around the corner — the 2000s have been notably quiet on the ska front — but in Houston it's been here the whole time. Look no further than Slackfest headliners Los Skarnales for the reason why: During the past decade, Skarnales' relentless coupling of ska with punk-rock energy and savory Latin rhythms has made them one of Houston's most popular groups, and Felipe Galvan's raucous ensemble shows no signs of stopping. Brooklyn's always-welcome the Slackers are more in the classic-ska mode, while Houstonians Ryan Scroggins & the Trenchtown Texans and The Umbrella Man both use ska as but one of many ingredients in a multicultural sound. Be that as it may, Slackfest — which begins at AvantGarden with Texas City gypsy skankers Come See My Dead Person, moves over to Mango's for Room 101's twisted skronk-blues, and finally to Numbers for the bands mentioned above — is an excellent chance for Houstonians to enjoy ska in all its many forms and flavors.