I just came across this Ted.com video by Johnny Lee. In it he demos his Wii Remote hacks... taking a standard $40 game part and adapting it to power things like a digital whiteboard, a multitouch display and a head-mounted 3-D viewer. (Other projects by Johnny at Carnegie Mellon U are here)
His brilliant tenet is this: Millions of $ have been spent developing foundational technology like the Wii Remote -- which can then be applied to dozens of *different* applications. Factor in the ability of YouTube to share ideas, and you've got a fantastic acceleration of technology and solutions.