The Temple of Notch is a Minecraft world you can play that's dedicated to Minecraft's creator Markus Persson.
To enter the Temple of Notch, you have to throw a gift into the well, and then the entrance will open. Once you're inside, you'll see the face of Notch carved into a giant cliff. The Notch-god will then judge you!
This is a fun Minecraft world, that shows you what you can do with some creativity! It's not the biggest ready made world you'll find, but it is amusing. To play, simply unzip the folder and move it into your Minecraft Saves folder. It will then be available to play next time you open Minecraft.