I have huge lists of ideas for projects (everything from designing my own index cards, to a ridiculous idea for demonstrating the curvature of the earth), lists of books that I want to read, lists of lists of books that I might find interesting, lists of music to listen to, and smaller lists of things like places to go, things to see, and skills to learn.
By keeping track of the things outside my head, it seems to declutter my everyday thoughts and I can focus on doing meaningful work on the few things I choose to work on right now. Obviously projects and reading are two things that are important to me, so I try to do a bit of each every day when possible. It doesn't always work, but it works better than when I had no such system.
Make some fun IoT projects with a raspberry pi. https://pi-hole.net https://blog.adafruit.com/2018/07/13/how-to-make-a-raspberry...
Buy a cheap car with known (but not massive) problems and Learn how to fix them.
Read or watch Richard Fineman’s physics lectures. http://www.feynmanlectures.caltech.edu
I highly recommend you check out "The Shallows: What The Internet Is Doing To Our Brains", by Nicholas Carr [0].
[0] - https://www.amazon.ca/Shallows-What-Internet-Doing-Brains/dp...
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