David Johnson-Davies designed a minimalist ATtiny85-based watch using 12 LEDs, arranged like a clock face, to show the time in analogue-style. He writes:
To show the time you press the button on the watch face, and the time is then displayed for four seconds. It lights one LED to show the hour, and flashes another LED to show the minutes to the nearest five minutes, like the hour and minute hands on a clock. If only one LED lights up you know that both hands are pointing to the same hour mark.
Tiny LED Time Watch – [Link]