Minecraft is probably the single most successful indie game ever made. It has sold almost 3 million copies, and it isn't even out yet.
It's success is well-earned, though. Mojang created a remarkably simple tool set and let players run wild. We've already seen a fully functional computer, loads of pixel art and even the planet earth. Now we have yet another example of obscenely imaginative people with perhaps a tad too much time on their hands.
Shrogg2 has created a 3D printer using red stone and pistons. It's really interesting to watch, and I must admit I'm thoroughly impressed with his knowledge of electrical engineering.
As Minecraft gets closer and closer to its full release, I'm excited to see what else people will come up with. I'm half expecting people to cure cancer, solve the energy crisis and invent faster-than-light travel with their own animal-based space program.