Even at their mangiest, the movies of Cheech and Chong have had one thing going for them: the randy, blissed-out exuberance of Cheech Marin-he's like the happiest (and funniest) vagrant alive. On the other hand, Tommy Chong, with his three-puffs-to-the-wind deadpan, is an utterly passive straight man (assuming it's possible to use the words ''straight'' and ''Tommy Chong'' in the same sentence). In Far Out Man, his first solo outing, Chong, playing a hippie who returns to civilization after 20 years, isn't just passive; he's not quite there. Far Out Man is one lame '60s-burnout joke after another. The movie is so weightless it barely gives you a contact high.