Who knows if Portal 3 will ever come about, but if it does, I have a feeling that Valve may snatch up the students behind DigiPen project Perspective: A 2D platformer played on the walls and objects of a 3D space. In a bad sidescroller, the camera gets in the way. In Perspective, the player is the camera and it's their job to get out of the way. It's a difficult concept to grasp until you see it in action.
Much like previous DigiPen-projects-turned-Valve games Narbacular Drop and Tag: The Power of Paint, there is an interesting idea behind this project that could be expanded through Valve's resources and financial backing. While Perspective is plenty of neat on its own -- twice as true of a student project -- I can only imagine how these mechanics could make our heads spin by being thrown into Portal's puzzle labyrinths.
Perspective is a free download, currently available for PC. Give it a shot and let us know if you see the future of Portal in it or just a fun student project that could become its own thing (like Distance).