The document discusses liquid cooling projects for ODROID boards. It describes a liquid cooling system built for an ODROID XU3 computing cluster consisting of 10 ODROID-U3 boards, 1 ODROID-XU, and 1 ODROID-XU3 connected to a water cooling loop. It also details a liquid cooling project for an ODROID XU+E that took 5 weeks to complete and cost $950, involving a complex water cooling setup with 6 fans, LED lighting, and a customized power supply. Temperature tests showed significant cooling for the ODROID hardware.