Say It Isn't So features Heather Graham and Chris Klein fucking each other's brains out until they discover they're sister and brother. Yup, it's an incest comedy produced by Peter and Bobby Farrelly, and directed by their protege J.B. Rogers, but with a script by Peter Gaulke and Gerry Swallow that is minus a shred of Farrelly wit. Welcome to the film universe where crap (Exit Wounds, The Mexican) cashes in, and movies of originality and imagination go begging. The latter are either film-festival favorites fighting for distribution or films that do manage to get released and then have to battle to stay in theaters for more than a week. Here are two of the best of this courageous breed.