Go buy a Merge Cube right now if you want to play with AR. Seriously, just go do it.
While Apple prepares to roll single-point augmented reality to the entirety of iOS this Fall, and Google prepares to release several phones with spatially aware camera arrays onboard for whole-building augmented reality, Merge Labs wants to show you a $15 block of foam you can play with. It looks like something you'd see as a prop in a sci-fi TV show from the 90s with no budget, but when you point you phone at it what happens on the screen is nothing short of amazing.
It's called Merge Cube, and you're really going to want one of these if you care at all about Augmented Reality.