 One of Grimshaw's most "memorable, iconic" posters promoted the John Sinclair Freedom Rally, held in Ann Arbor on December 10, 1971, featuring performances by John Lennon, Yoko Ono, Stevie Wonder, Bob Seger, Archie Shepp and Phil Ochs.Speakers at the event included Bobby Seale of the Black Panther Party, Jerry Rubin of the Yippies, and beat poet Allen Ginsberg.Sinclair was freed within days of the rally.