Once upon a time this site supported teaching experiments with a pre-release version of App Inventor in Fall 2009 and Spring 2010.  You almost surely want to go to the current MIT App Inventor site at appinventor.mit.edu.

If you were part of the original pilot site and want to see the original material of that site you can see it here.  Note that that original pilot site is access controlled and is only available to participants in that pilot.