This is my first foray into building something with a Raspberry Pi, using a Raspberry Pi 3B+ and a Sunfounder 10.1" monitor:
Everything this clock is set up to do, except for indoor temperature and humidity, can be see on this web site: https://weather.shetline.com/
Since this clock sits on my dresser and has the potential to be too bright at night, one of the things I built into the web client was a user-settable dimming schedule. I've currently got the schedule set to dim the clock 55% between 11:00 PM and sunrise.
Besides showing time and date, the clock shows the current positions of the planets along the ecliptic (drawn as smaller dots when below the local horizon and larger dots when above the horizon), sunrise and sunset times, moon phase, current weather conditions, a four-day forecast, and weather alerts. By adding a DHT22 sensor you can also get indoor temperature and humidity.
All of the code, along with what I hope are fairly complete set-up instructions, are available on Github: https://github.com/kshetline/aw-clock
I've got the Pi running a node web server on localhost:8080, and automatically starting up Chromium in kiosk mode to display the web client. I've tried my best to make sure that the set-up runs as much like an appliance as possible, booting up as a clock as soon as it's powered on, with what I hope is pretty good chances of recovering smoothly from power loss.