touchpy: Python framework to build media rich applications on top of tuio framework. This gives as possibility to use multitouch screens for input, and It doesn't depends on one implementation only. One part of the project is also a compiz plugin, which will be used as a debuging output, and a overlay for drawing fast pointers, displaying radial menu etc.
BBTouch: BBTouch is an open source project. It is a Cocoa/Obj-C implementation of a multi-touch surface software package.
In addition, let me add another multi-touch frameworks…
Bespoke Multi-Touch Framework: It is a software framework for developing multi-touch interfaces paired with vision-based multi-touch systems.
Touché: Touché is a free, open-source tracking environment for optical multitouch tables. It has been written for MacOS X Leopard.