Oh, they actually allow you to download it for free now, IIRC. Maybe they just figure it's so obsolete, no one would bother to port it to a newer system? To be fair you can get the same effect with newer granular synthesis software manually, th0nk was just cool in how you never knew what you're going to get out of it, leaving the result to chance.

(direct download link http://www.audioease.com/download/thOnk_0+2.sit.hqx )