It's not exactly fair: Richard Jackson (who cleverly mocks the heroic aspirations of modernist painting) is an admired artist, but Paul McCarthy (whose mockery of the same is savage, disgusting, and suicidal) is an art planet. Tonight the two Californians share a stage as the aging rebels representing Target Practice, SAM's summer exhibition about the worldwide skewering of painting after World War II. Will they blow your mind? Try them. (Seattle Art Museum, 1300 First Ave, 654-3121. 7 pm, $8.)