It is not a Mac, but the machine has generated a huge lot of buzz since its inception.
The XO, also known as the OLPC is there for you to get !
Here are various links that actually tell something about the machine and the concept...
XO, the next lisp machine ?
Ivan Krstic's Google Tech Talk
One Laptop Per Child (New Version), Reviewed by 12-Year-Old
And of course, Alan Kay's keynote at EuroPython 2006 part 1, part 2 and part 3, with a summary by Guido van Rossum
Computing does not have to be dumb !