"The Mighty" comes from director Peter Chelsom, whose "Funny Bones" is one of the most interesting comedies of recent years. The new picture is an adventure-comedy-drama aimed at family audiences, about an adolescent boy with a degenerative disease and an ungainly neighbor with an overweight frame and an iffy domestic history (his dad's in the slammer for killing his mom), both of whom are laughing stocks among the notoriously insensitive junior-high set. The two outsiders pool their talents into an unlikely partnership, with the diminutive sick kid literally riding the shoulders of his towering friend as they fight neighborhood enemies and perform an occasional good deed, all the while fantasizing that they're gallant knights in good King Arthur's day. "El Topo Meets Camelot," you might call it. Chelsom is a very inventive filmmaker, and the picture's two fine juvenile performances are flanked by an impressive roster of adults including Sharon Stone, Gena Rowlands, Harry Dean Stanton, Meat Loaf, and "X-Files" star Gillian Anderson in a wild turn as the latter's feisty wife. The movie is no more subtle than the usual Hollywood family fare, but it has a lively spirit, a gentle heart, and a number of funny lines. It should do well at multiplexes when Miramax decides to release it, and in all it thoroughly deserves to.