Sure, writing a note on a piece of paper and plopping a magnet on it to stick it to a refrigerator works perfectly fine. But if you have an old Kindle around and want an over-engineered, but fun new way to leave fridge messages, DIYer Pete Vojtek shows you how to display notes on a Kindle.
Once you're done with the setup, you'll essentially send an email to an account, a Raspberry Pi will check for new emails then render the email as a web page, and the Kindle will display that page. It's totally absurd, but a fun idea nonetheless. Head over to Peter's GitHub page for a full guide.