Like a lot of exotic-sounding styles with long regional histories, Cajun music is something a lot of people outside of Louisiana understand in only touristy, superficial terms. But an encounter with the Lost Bayou Ramblers can drive home what a dynamic musical tradition it is. Two of the band members — fiddler/singer Louis Michot and accordion player/builder Andre Michot — have Cajun dance music in their blood; their dad and uncles launched the long-running acoustic outfit Les Freres Michot more than a quarter-century ago. On the Ramblers’ latest album, Mammoth Waltz, the younger Michots, guitarist/singer Cavan Carruth and drummer Paul Etheridge take a psychedelic garage-rock attack. They still sing in French, they still play choppy, swinging, fiddle-sawing and squeezebox leads, but they work in plenty of distortion, surreal textures and primal, punkish grooves. Their excellent Korey Richey-produced album boasts guest appearances from the likes of Dr. John, the Violent Femmes’ Gordon Gano and Scarlett Johansson. Don’t let the fact that the Ramblers are playing the Bluebird fool you; they’re known for getting wild.