Why not try something very different outside of programming? Such as learning to play an instrument, a foreign language, Jiu Jitsu etc.
In the long run, such offbeat pursuits have a multiplier effect.
I learned Banjo a few years ago while freelancing. The trick is to hang it right next to your desk. You'll play it way more and keep playing it as a nice break (vs watching youtube videos).
Oh, I already have lots of outside hobbies. I'm just trying to make work more fun (I do realize how privileged I am to even think this.)