The Cleveland Institute of Art Cinematheque continues its four-part celebration of the 50th anniversary of the San Francisco-based Canyon Cinema with tonight's program, Decodings, named after Michael Wallin's 1988 found-footage masterpiece of the same title. Tonight's selection of films also includes Lawrence Jordan's Duo Concertantes and Will Hindle's Billabong, an" impressionistic" documentary of a boys' youth camp. The program begins at 5 p.m. Tickets are $11, or $8 for Cinematheque members and students. (Niesel)