They Thought It Best, an assemblage by G.C. Guard, is included in the exhibit "Mixed Messages," a survey of work by alumni of Columbia College's graduate program in interdisciplinary arts, which celebrates its 20th anniversary this year. The show includes paintings, photos, sculpture, artists' books, puppets, and installation and video art. An opening reception will be held this Friday from 5 to 8 at Artemisia Gallery, 700 N. Carpenter; it's free. Call 929-0248 for more info.