Manuel Kerssemakers, Jeppe Tuxen, Julian Togelius and Georgios Yannakakis have done something remarkable. They've created a computer program that does Nintendo's job. Sort of.
For their paper called A procedural procedural level generator generator, blogged today by Gamasutra, they built a system that's able to randomly generate levels for Infinite Mario Bros, the never-ending Mario tribute developed by Minecraft creator Marcus "Notch" Persson.
The way they've designed the program to build the levels is fascinating, creating limits on the number of certain items while encouraging enemies to spawn, I guess, sensibly.