I like to collect alarm clocks and desk clocks. Over the years I bought many at flea markets and second-hand shops. Sometimes I restore them, or rip out the gears and put in a DF77 radio-controlled clockwork powered by a battery. I also make digital clocks using 7-segment displays. All of these projects make nice gifts, I've given a few to special people.
Clocks amaze me - the same basic concept has been re-imagined and re-designed and re-invented over the years with different colors, layouts, typefaces, hands, and endless ideas.
I've made a few clocks myself, using LEDs, 3D printing and experimenting with different form factors.
ESP32-based “cyberclock”, more details at 
esp32-cyberclock
Experiments using round TFT watch displays, and controlling several at the same time.
A custom “Nixie” style clock, custom PCB with 2020 WS2812 LEDs.
