If you've never tried R.O.T.O.R.,, that's my personal favorite. Everything in the "Rifftrax Essentials" section pretty much rules.
Yeah, I picked up ROTOR the last time they did one of these. Hoping to find a good sci-fi or fantasy one.
For fantasy, try Jack the Giant Killer or Ator if you haven't seen them. For Sci-Fi, try Mind Ripper, Alien Outlaw or Deadly Instincts.