Fireworks
Here’s one I did for the Pyrotechnics Guild International convention in August 2012 which won the ‘Best Large Show’ award:
This was fired using a computer-controlled firing system I built myself. There were three stations, each with its own controller:
Inside is an Arduino, plugged into a custom PCB I designed with eight STMicroelectronics L9733 driver chips. Each has eight configurable high/low side driver outputs and an SPI, allowing me to drive up to 64 cues with just eleven Arduino pins (eight chip selects plus the SPI lines). I can swap out modules inside the controller to allow for wireless or wired control.
Each station looked like this when wired up: