There is a game called Against The Wall, developed by Michael P. Consoli. It's a fantastic game, as I've always been stumped at how the game creates an infinitely spanning wall.

In the game, you can fall forever, and the wall will keep spanning. I can fall as long as I like, and still be able to climb back to where I was before. The game is developed in Unity.

How can a game do this without crashing, or creating some kind of memory overload?