Small binary clock
You simply must love a clock that most people can't tell time from.
A small binary clock is built on 2.5x2.5cm board with PIC16F84 microcontroller and 4 LEDs. When "show" button is pressed, current time is displayed in BCD fashion showing tenths of an hour, than ones of an hour followed by minutes. This is a cool project for beginners although only HEX file for PIC is available. If someone wants to make their own firmware for the clock, there is a Single tube nixie clock with timekeeping functions and almost all job already done.
[ Source: Maco ]