So what do you get if you mix a saxophonist in pointy devil horns with a gas mask-wearing bass drummer and a horn player dressed like a Norse princess? You get a butt-kicking good time, is what. To be more specific, you get the Brass Balagan, a horns-and-percussion ensemble from Burlington, Vermont. The group — I counted about 20 members — was tearing up Chester Street in Somerville’s Davis Square a couple of Saturdays back during the HONK! festival, an annual rip-roaring celebration of brass bands, community, and activism. Now in its seventh year, HONK! has become a must-see tradition in my house, a weekend-long explosion of rhythm and sound. Nearly three dozen bands took part this year, the most ever. Swing, dirges, klezmer, Mexican numbers, New Orleans-style — HONK! showcases it all. The crowds were deep, thick with dancers, stompers, and bobbers. People climbed trees, stood on benches, perched themselves on utility boxes. At one point, the Detroit Party Marching Band had the whole square jumping, one of its associates thrusting into the air what appeared to be a golden hen on a stick. It’s hard to explain, so just trust me that it made all the sense in the world.