Free: Scarypiano
Scarypiano came about almost by accident - one of us was writing a review of some software that's designed to be used for making monster voices for video and game post-production, and he tested its batch processing feature on some piano samples. You can read the review on Bedroom Producers Blog. Since the piano samples happened to be the public domain samples from the University of Iowa, and Halloween wasn't far away, we thought it would be fun to release the results upon an unsuspecting world as a special Halloween freebie.
Scarypiano has three voices - one is made from all three original velocity layers, another is made only from the loud layer, and the scariest voice is made only from the medium layer. It's a 342 MB download and contains 430 16-bit WAV samples, an SFZ mapping and even a GUI for Plogue Sforzando complete with bloody eyeballs for knobs (thanks to Plogue for helping out with the GUI). We recommend using automation with the controls, even when Scarypiano isn't playing any notes, just to make the eyeballs roll around.