Some planets in the universe are tidally locked with their stars. This means that their rotation speed is the same as their orbit, so one side is always facing its star, and the other is always facing away from its star. Because of this, one side of the planet will always be scolding hot, while the other side will always freezing. However, there is a small section in the middle where the temperature is perfect, water can be a liquid, and normal life can be sustained. I think it would be nice if we had planets where one half was volcanic and the other half was frozen, but the middle would be forest. It would look something like this: Also, the volcanic side would always be daytime and the freezing side would always be nighttime. So, the sun would only move when you walk around.