Make a Big LED clock with arduino and RTC module to make it as a Real Time Clock.
FPGA based binary clock, which uses GPS for the time reference.
Use an RGB matrix and a micro:bit to display the time with an awesome game of PONG. Made with love and TinyGo.
Remember the days when you would sit listening to WWV time signals on your shortwave radio (tick, tick, tick…At the tone, the time will be…)
This project uses an ultrasonic sensor to allow a "hand wave" (no touch!) to trigger a series of LED's and the Happy Birthday song twice