Learn to play the Guitar or I guess any musical instrument. I've been playing for the last 1.5 years and it's a great way to relax, clear you mind, prove to yourself that you're capable of taking on new things. It's a lot of fun too!
EDIT: The actual "why didn't I do this sooner" moment comes after a month or so where you get fast enough with chord changes that you can actually play something :)
EDIT: The actual "why didn't I do this sooner" moment comes after a month or so where you get fast enough with chord changes that you can actually play something :)