It is a pretty common first project to use an Arduino (or similar) to blink an LED. Which, of course, brings taunts of: you could have used a 555! You can, of course, also use any sort of ...

The WatchDuino is exactly what it sounds like, an Arduino-based wrist watch. The component list is short and inexpensive. The meat and potatoes consist of an ATMega328, crystal, Nokia LCD screen ...