I've been using my HP TouchSmart PC at work with students with disabilities. I'm experimenting with the NUI Suite SnowFlake on my TouchSmart.
The software utilizes a plug-in from NextWindow that allows for more than one touch on the screen at a time. I found that interacting with the Particles application delighted students with severe autism.
NUI Suite Snowflake Multi-Touch Applications (Demonstrated on a touch-table, but the effect is similar on the HP TouchSmart.)
Note: The Particle application starts at 3:00 - the demo is set to show how it could be used as a social activity in a bar, but it is clear to see the possibilities for use with students.
Update: Here is the SnowFlake application running on a TouchSmart:
More about the HP TouchSmart PC in education:
Interacting and Communicating with HP TouchSmart Notes: Photos, Video, Audio, and More
Definition of Joint Attention from UConn:
"Joint Attention is the process of sharing one’s experience of observing an object or event, by following gaze or pointing gestures. It is critical for social development, language acquisition, cognitive development…"
Joint Attention Study Has Implication for Understanding Autism Science Daily, 9/29/07
Asperger-Advice: Joint Attention
Autism Games: Joint Attention and Reciprocity
Why is joint attention a pivotal skill in autism?
Philos Trans R Soc Lond B Biol Sci. 2003 February 28; 358(1430): 315–324.