This is happening right now! Mario 64 boss hog Siglemic, who actually holds a handful of other Mario speed run records, is now in the process of trying to reclaim his 120, full completion Mario 64 speed run record. You can watch it, live!
I've always appreciated and loved the skill involved in speed runs. I think it's part of the reason why I love Trials so much. But I find it particularly awesome to watch a guy like Siglemic play a video game I'm totally familiar with, and take things to the stratosphere. This is a very fun watch.