This is something i recently finished: i made one for myself, and 2 as new-year presents for my 2 nieces. It actually start at a project some years ago: i just had an itch to make something that would last for a long amount time on a few batteries. Initially i thought about a weather station or something similar, but that requires constant measuring. So in the end i just went with something that shows a new quote every 12 hours.
Of course to really make it last, im using an e-ink screen. I am driving it with a firebeetle 2 esp-32. Those firebeetles have a very low "quiescent" current (i have to google that word every time), especially when you cut the specific lead on the board to enable this. I am also downclocking the esp etc ... to achieve the minimum power draw.
First, i had it running inside a cardboard box:
It ran like this for 18 months, and during that period, there was barely any voltage drop on the batteries, which kinda amazed me. As you can see the idea was to 3d print an enclosure for it, but in the end i went with wood. I think i enjoyed this more than i would have just 3d printing it.
And this is how it looks now:
Special thanks to ZinggJM for his excellent library, and the support we gave me a while back on this forum!