Seven-segment LED displays are great for creating clocks. Just link four of the units together, with a couple dots as a colon and proper driver hardware, and your clock face is ready to go! Or you could make something like “Frugha,” and construct what could be the most incredible seven-segment clock we've ever seen, using not four, but 144 seven-segment display modules to tell time in the form of huge numbers.
The clock is built on a giant PCB, with an Arduino Nano and an RTC for overall timekeeping. 18 MAX7219 chips are used to drive the 144 displays. If that's not impressive enough, note that this works out to 1,008 LEDs that can be controlled separately.
The resulting clock's digits appear pretty organic, rather than “pixely,” perhaps owing to the way that each unit can be individually arranged. And if you were wondering, the clock can indeed be set up to reveal 36 clocks on its face, instead of the large digits for which it was designed.
One could picture a host of other applications for this unique array, ranging from scrolling information to showing different time zones simultaneously. Arduino code along with Gerber files are available on the project page, so maybe we’ll see copies, or even enhanced versions in the future!