Have fun at Oktoberfest, rain or shine. The “Mad Bavarian Brass Band”, a New England favorite, will circulate among the crowd playing traditional polkas, sing-alongs and happy music of all kinds. “I am Not a Gun’ will open on stage at 11:00 a.m. featuring Larry Keegan on guitar, Josh Dwyer on bass and Jonathan Chiros on drums. “The Angry Tides” will play at noon. This small band out of Billerica features David Blois on bass and lead vocals, Dave Saulnier on lead guitar and Justin Desilva on drums. “Fireking” will take the stage from 1:00 – 2:30. Lead Vocalist and Manager Anthony Kacznski describes the band’s genre as royal rock. Backing Anthony are bass guitarist Drew Morrison and drummer Smitt E. Smitty. Closing from 3:00 – 4:00 p.m., the creative “Somerville Symphony Orkestar” plays all-original Eastern European punk at many area festivals, including Boston’s First Night.  Six members, Joel Edinberg, Pete Fanelli, Travis Pullman, Richey Tally, Matt Ellis and Penelope come up with a joyful Klezmer sound. Hear it live. Sample beer. Eat German food. www.rotaryclubofconcordoktoberfest.com.