From ABBA to ZZ Top, Tchaikovsky to Nirvana, a whirlwind of genres performed with 16 hands, no drums, no guitars, just vocals and ukulele magic. $41–$101. 3 p.m. Weill Hall at the Green Music Center. Rohnert Park Expy. & Petaluma Hill Rd., Rohnert Park Tickets: tinyurl.com/5are8fdk.