Puredata is basically a free precursor to the aweseom MaxMSP. Patches can be shared between them. Great for procedural music generation and multimedia, but has a bit of a learning curve. I'd recommend the book 'Loadbang!' by Johannes Kriedler, which is freely available online, if you get stuck. The help files are also great.
Ottimo strumento per creare strutture anche molto complesse, non molto intuitivo ma eccellente nel comunicare con altro hardware mediante la facile configurazione di porte seriali.