If ever a title told the truth, it's this one. Sheer venality is the only reason anyone could have thought 1994's DUMB & DUMBER merited a prequel (rather than a sequel, presumably because Jim Carrey and Jeff Daniels wouldn't commit to reprising their roles). But even given its mercenary origins, it's flat-out astounding that this inane farrago ever got made. Leads Derek Richardson and Eric Christian Olsen may be carbon copies of Jeff Daniels and Jim Carrey, but their copycat performances produce an even more tasteless product than the original. After being home-schooled for years, Harry (Richardson) is forced by his mother (Mimi Rogers) to give up his imaginary frie...