Mario Maker

Create and share your very own Mario levels.

Somehow I missed this when it was posted a few days ago (nice hunt, @webjoe). They just revealed a new trailer at E3:
If anyone is still on the fence about Super Mario Maker, check out the final stage of the Nintendo World Championships 2015 where the contestants played this game. I was completely on board after that segment.
I'm honestly not sure what to expect from this... Here's really hoping there is better social network / sharing support for this content by Nintendo. The Sharing/Upload your custom stage aspect of Super Smash Brother is a bit of a joke. No search results, only view by country, 100 items at a time. You can view content by browsing a users Miiverse, however the content they posted is only available for 30 days. Meaning.. super popular content posted on reddit? After 30 days that web page is pointless, the content is removed from Nintendo.