Behold! The Uncommon!
Uncommons often felt to me to be some of the sweetest cards in their respective limited formats. You get to play with them more than the rares, and they're usually cooler than the commons. I've wanted an evergreen Cube that I can have in paper and play with newbies and vets alike. I know a lot of people like Pauper Cubes so I thought, that's cool but what about Mono-Uncommons.
All the cards in the cube have to have been printed at uncommon. No commons, Rares, or Mythics allowed. This most recent version is mostly built around the Uncommon battles and planeswalkers. Just to have some signposts.