Robert Henke has released Granulator II, a free Max for Live synthesizer based on the principle of quasi-synchronous granular synthesis.
It creates a constant stream of short crossfading sections of the source sample, and the pitch, position and volume of each grain can be modulated in many ways to create a great variety of interesting sounds.
Granulator II also offers two multimode filters in series to further shape the resulting timbre. Granulator II is the latest incarnation of a series of granular based synthesizers I wrote for my own usage since the invention of MaxMSP in 1997.
The instrument is a free download (CC BY-NC 3.0 license).