I needed a patio light for evenings spent hanging out on the balcony. A proper lantern would have been a bit much, and a flashlight wasn't quite what I was looking for. So with an old mason jar, some LEDs, resistors, leftover perforated PCB, and a spare atmega chip sitting on the bench, I decide to just slap one together.
It was obviously a bit of overkill using the chip for this, but it worked out. The LED's are arranged at different heights and facing different directions. It cycles through light doing a PWM routine, resulting in a firefly sort of effect.