We'll be building an application for a non-profit in a period of about 3 hours, using different web application frameworks. During the course of this, we'll be showing everyone's progress with various frameworks and sort of encouraging some friendly competition between the different camps. And everything will be released under the GPL.
So far, we've got interest from 37signals for RoR and the CakePHP and web2py core developers. Also, there will be free food. Any interested parties?