Poet, teacher and photographer Thomas Sayers Ellis lives in Brooklyn, but he grew up on D.C.’s east side, where go-go’s syncopated rhythm is the community’s heartbeat. His photographs of musicians and fans are collected in “(Un)Lock It: the Percussive People in the Go-Go Pocket,” a Gallery at Vivid Solutions exhibition that also includes three 20- to 30-minute performance videos and a few of those day-glo, block-letter placards (printed by Baltimore’s Globe Posters) that used to publicize go-go concerts.