This clever hack on github provides all the code you need to set it up so that your Raspberry Pi checks a given Gmail account and renders the most recent message as a webpage, which the Kindle web browser automatically refreshes and shows on the screen. A couple of adhesive magnetic strips to hold the Kindle to the door, a long enough charger cord to keep it plugged in, and you’re done!
It is a bit of an expensive way to display messages on the fridge door, but nonetheless it’s a clever, relatively simple way to repurpose an old e-reader to do something new. Neat idea! (Found via Lifehacker.)