I saw https://hackaday.com/2020/04/08/what-day-is-it/ and printed both the hemisphere clock and pointer. I wanted to have some progress during the day, instead of an update once per day, so I started updating the code to provide an hourly update of the pointer.
Then it went off the rails...
I obtained a MHZ-19B CO2 sensor which I use as a measure of the indoor air quality of my little basement workspace. So I wanted to expose these measurements in some way, so I used a standard 1602a LCD panel to display the temperature, humidity, and CO2 level. Then I was interested in providing this data for further analysis, so I added XML and JSON interfaces to pull the data as well as a UDP push source, and an auto-updating web page view.
I finally added OTA update capability so I don't have to walk 3 feet across my room, unplug the power source, and plug it into USB to reprogram it.