Already released in 1997 this is still a fun a usefull tool for some ad-hoc sound mangling in your mixers channel. It offers a resonant filter (LP/BP) with envelope follower and distortion. A simple digital delay with feedback control is added behind. The actual (supported) versions are available for AU only, though. Have a look at the Prosoniq product page.
Some granular madness is featured by Koen’s KTGranulator which offers some delay and pitch-shifting effects based on a sort of granular re-synthesis. Great for some unusual audio effects and tweakings. Both, PC and Mac versions available – check out his site at smartelectronix.com.
Large artistic amounts of audio timestretching effects are easily achieved with Paul’s extreme sound stretch tool. The bits for PC are available at sourceforge.net. Extremely useful to create drones and ambient stuff. A short overview and tutorial is available here.