Fan Controller
Disclaimer: I built this my senior year of high school, it shows in my soldering and the quality of the code. Code and PCB design are available here.
A general purpose PC fan controller. 6 fan ports, 2 I^2C temperature sensors, controlled via USB. Firmware written with avr-libc and LUFA
My custom controlling software is certified to be 95% less likely to stop working spontaneously or sporadically crash your computer than Corsair's iCUE software.