OK, we’ll admit that combining these two October institutions was a little unfair. But the best part of the four-day HONK! Festival of Activist Street Bands is the parade from Davis Square down Mass Ave. to Harvard Square’s massive Oktoberfest celebration. The moment when the freak-flag-flying marching bands and revolutionaries converge with the Sperrys-and-button-down Harvard crowd is like nothing else. And if you can grab a spot in a beer garden to watch the bands funk it up on the main stage, even better.