Octagon Audio has released PlugData v0.6.1 as a plugin, with a new GUI.
Pure Data is an interactive programming environment that allows you to process, synthesize and modify real-time audio signals. It also has a system for control messages.
PlugData is a new Pure Data spinoff with a more modern GUI, and the ability to run both as a standalone and as a DAW plugin. It offers musicians an environment to build their own effects and instruments.
PlugData also ships with two large libraries of extra objects (ELSE and cyclone).
Version 0.6.1 comes with several bugfixes, includes the new [button] object.
Price: Free. The new version is available for download here.