A history of Nasa's "game changing" programs.
Seems that Nasa comes out with these "Game Changing" new plans every 5 years or so.
X-33/VentureStar(SSTO Game Changer)...CANCELLED 2001
Project Prometheus (Advanced Propulsion & Power Systems Game Changer)...CANCELLED 2005
Project Constellation (Going beyond LEO Game Changer)...CANCELLED 2010
Obama Space (No Access to Space Game Changer)...CANCELLED TBD