Marcus Tsutakawa and David Upham share the podium for a Halloween concert, a good, unhackneyed program of spooky music by Franck, Gounod, and Grieg. It's an interim year for the SYSO, still searching for a music director to lead their high-school-level orchestra, a challenging post at the organization's best and most visible group (as one insider explained it to me, making music with the kids is about 20% of the job, while the rest is spent on the phone placating irate parents demanding to know why Kaitlynn didn't make first chair). But the kids don't care: Their ego-free enjoyment radiates from the stage whenever they play—with or without gorilla suits. Benaroya Hall, Third and Union, 206-362-2300 or www.syso.org. $8-$35; come in costume to get a discount. 3 p.m. Sun. Oct. 30.