Vaudeville pratfalls, sight gags, and ribald one-liners have always been producer-director Mel Brooks's mainstay. Here the jokes are tossed haphazardly from Brooks's gag bag and roll out ineffectively in a spoof of the "Star Wars" films. The plot, such as it is, offers pretty princess Vespa (Daphne Zuniga), daughter of kindly King Roland (Dick Van Patten), as a kidnap victim of evil Dark Helmet (Rick Moranis). Space adventurer Lone Starr (Bill Pullman) and his sidekick, Barf the Mawg (John Candy), are assigned to retrieve Vespa. Thus begins a ridiculous odyssey through space with blazing rockets, death rays, and firefights among the stars, resulting in a slaphappy ending. This is a formula film for Brooks, one that has long ago worn out its welcome with viewers. Only Brooks shines momentarily as the president of the planet Spaceball and, in a dual role, as that of his crinkled, ancient adviser, Yogurt. It's mostly forced humor all the way, a movie that rarely measures up to adequate kitsch. Aimed at younger audiences, SPACEBALLS misses its mark.