Grafiti is available to download from Sourceforge via svn.
svn co https://grafiti.svn.sourceforge.net/svnroot/grafiti/trunk grafiti
The downloaded folder will contain the source code and the Visual Studio solution, that can be opened and compiled also with Mono Develop. You can try the demo with a multitouch table + reactivision or with the newest Tuio simulator.
It’s an alpha version, and it needs to be tested more than I could do, not having a multi touch table yet. Feedbacks are welcome, expecially the negative ones. Soon I’ll publish a guide.