Anything related to lucid dreams? Think of the ability to utilize the 8 hours of sleep for something productive or recreational. It will take atleast a decade before VR catches up with the level of detail you get in lucid dreams. Something that makes them more accessible for people, so that everyone could get this "me time" every night would be amazing.

If you want to try, just keep on asking yourself if you are awake throughout the day. Try reading something, it's difficult to read something on dreams. Or try using electricity switches, they normally don't work in a dream. Sooner or later you would find while doing this that you are in a dream. From there, sky is literally the limit. Imagine whatever you want, fly across mountains, travel in spaceships, etc. till the time you wake up.