It’s the longest Bumbershoot ever—11 days. Roger Downey, arts editor of Argus, organizes an “Alternative Theater Festival” starring the San Francisco Mime Troupe. Oscar Peterson is the big name, and a largely unknown singer named Jimmy Buffett wins over Bumbershooters with his sun-drenched party songs. Wearable art is the kick of the festival. Program highlights are available by touchtone phone via “Chester,” Bellevue Community College’s computer.