Minecraft series -- Etho's Lab, Sky Factory

If you're a huge nerd like me and like watching Let's Plays, my current favorite is the Modded Minecraft: Sky Factory, featuring Etho, VintageBeef, and PauseUnpause. They start with a single tree on a piece of dirt in an otherwise completely empty void, and using a bunch of interesting mods they're slowly building a world out of it. It's kind of a lot like Etho's earlier series, Crash Landing, another modded themed pack with some of the same mods.