Used records. Secondhand clothing. Homemade soap. Possibly-fenced items. The weekend flea market in the Ashby BART station’s western parking lot carries pretty much the typical swap-meet fare. But what sets Berkeley Flea apart? A loyal cadre of hard-core drummers and percussionists of all races and ages who gather every Saturday and Sunday morning to pound out the bazaar’s syncopated (and sometimes just plain discombobulated) soundtrack. Cowbells, timbales, congas, soda bottles, nearby trashcans, and pretty much any other beatable objects are fair game at this morning-to-night rhythm jam, which is open to anyone wanting to join. The drum circle is said to have originated some forty years ago at UC Berkeley’s lower Sproul Plaza before gradually migrating south to Ashby BART over the last decade or two. Today, it consistently lures curious onlookers who drift from their perusals of nag champa and chewing sticks to first gawk, then tap a foot, then, on occasion, burst into full-blown dance mode. How Berkeley can you be? Not much more than this.