This year's free arts festival, scheduled for July 18-20 and billed as the largest such event in the country, will also feature an increased emphasis on dance and all things motion-related. Included under Artscape's exhortation to "Join the Movement!" will be a "Silent Disco" in Pearlstone Park; "Dance!" featuring performances by Ballet Memphis and the Las Vegas Contemporary Dance Theater, at the Patricia & Arthur Modell Performing Arts Center at the Lyric; a street full of kinetic sculptures and other contraptions along Mount Royal Avenue; ballroom dancing on Charles Street; and an "Aerial Arts Arena" on Charles Street.