I was playing around with youtube and i found a great video series with excellent creations in minecraft. for those of you who don't know, Minecraft is a game where you use blocks of different materials and build whatever you want. You can build cities, occupy continents, or whatever. The way the game is programmed the world you build in is ever expanding and people make some breathtaking creations. Here is episode one in a series by Machinima. It's some amazing rollercoasters.