"Imagine." Sony. $29.95. Though their musical collaborations received the most attention, John Lennon and Yoko Ono also teamed up on numerous films, including this 1971 series of experimental mood pieces and sketches related to 10 songs from Lennon's "Imagine" album and two from Ono's "Fly" LP. The hourlong film, whose style ranges from surreal to burlesque, is indulgent at times, yet wildly imaginative at other points. On a historical level, its value today rests primarily in the fascinating glimpse it gives us into the ambition and independence of these landmark artists.