The parallac is a project created to bring several ideas together and also to do something fun in the spirit of classic super computing. It was made practical through the success of the parallella project and the amazing work they have done. The Cray-1 inspired design allows the combining of 8 computers (144 processors) into a relatively small package yielding about 208 GFlops peak (just from the parallella boards) at about 60 Watts.
This site is the home for the documentation of how to build such a system and will be the base for where to get some parallel computing software as it becomes available.
Checkout this blog post for an interview I did with the parallella folks.
The Verge covered the #parallac as well.