Update: It looks like the Tango tablet is available to purchase if you signed up to be on the list to buy one at Google I/O. The rest of you will, presumably, have to wait.
It looks like Google's Project Tango AR / sensor-beast tablet is headed to the Play Store soon, packing an NVIDIA Tegra K1 processor and a boatload of sensors. Not to mention 4GB of RAM and 128GB of internal storage, for some reason.
The Project Tango Tablet Development Kit Is On The Play Store, But It's Not For Sale Yet was written by the awesome team at Android Police.