The Flat Earth Society Orchestra (FES) mixes the rich Northwest European brass band tradition with oddball topsy-turvy creativity. Taking Belgian whimsy to a logical, irresistible extreme, FES straddles the border between multi-color surrealism and savvy skill. Composer, reed player, producer, and bandleader Peter Vermeersch, co-piloted by pianist and composer Peter Vandenberghe, have shaped their 15-piece orchestra into one of the most productive and thrilling bands of its kind. While Flat Earth Society’s compositions and arrangements betray 20th century traditions—from jazz to rock, exotica and contemporary music—they embody a decidedly forward-looking 21st century spirit. Quick-witted, effortlessly eccentric and always on the lookout for new challenges, Flat Earth Society is that rare beast: a constantly evolving orchestra that is most in its natural environment at a live show. This performance of the Flat Earth Society celebrates the Atrium’s 15-year anniversary in tandem with the band’s 25th—a happy reunion after FES’s previous performance in the Atrium in 2011.