The Summer Games Done Quick event recently ended, and I'm still thinking about an Ocarina of Time run:
It's best if you go in without too much knowledge of the run, but if you grew up playing and reading rumors on Geocities about what was possible, you'll love the process.
The team did a great job explaining the run, which relies on Arbitrary Code Execution and other tricks.
The summary video is great as well:
This particular run achieve the level of art, but here's a few other runs I enjoyed: