Here is a link to the OUYA web site. Here is a review on the Register site.
In short it is a console running Android, more or less comparable to the first Google Nexus 7 from a hardware point of view. It doesn't have access to Google Play out of the box, and has its own store. It costs about £100 and it's clearly targeted at hobbyists and tinkerers first. Never the less, it's slowly accumulating games and apps.
Did anyone experiment with developing for it, is it worth it in your opinion, and how does WADE fare when it comes to compatibility?