If you choose to celebrate this one don’t blame me. It’s National Leave Work Early Day.
This holiday was designed to shine light on the idea that getting your work done well and on time shouldn’t be tied to a 40 hour work week. i.e. you should be measured on the quality of your work and not the number of hours you spend at your desk.
It seems unlikely this idea is going to take off on a large scale, so the alternative is just to take a couple hours or an afternoon for yourself. Go for a walk. Read part of a book. Take a nap (always my first thought). Of course, you should clear this with your boss ahead of time!
Have a great afternoon!