Last week Paulig, a specialty coffee roaster based in Finland, unveiled a new coffee mug design called the Muki. This mug features a small and simple E-ink which is powered by pouring hot coffee into the cup. (Or at least that is what Paulig claims; if you look at the photos of the prototype you'll see that there is also a button battery on the circuit board.)
The Muki is probably the world's first smart mug, which in this case means that every time you fill it up the mug can sync with your smartphone over Bluetooth, enabling you to transfer an image and update the screen. The Muki also has a temperature sensor, and it will report back to the paired smartphone app with the current temperature of the coffee.
Here's the promo video Paulig released last week:
I can't find any details on the size of the screen, and it's not easy to judge from the photo. I do know that E-ink offers a couple screen sizes under 4" and that Pervasive Display also offers several E-ink screen sizes ranging from 1.4" to 2.7", and it might be any of the screens over 2".
There's also no info on cost, but I do know that the Muki is still under development, and is expected to be released next year.