I was given this HP Proliant DL180 G6 (Xeon E5506, 4GB RAM) without power supply. As a newbie in that domain, I was shocked by the size and weight of that thing!
HP ProLiant DL180 G6 Server Installation Sheet
HP 595491-001 ProLiant DL180 G6 Server (1 x 2.27GHz CPU/6GB RAM/No Drives) | eBay
HP ProLiant DL180 G6 - Dual Intel Xeon 2U Storage Server Review
Hewlett-Packard PROLIANT DL180 G6 Server HSTNS-2118-For PARTS/ REPAIR | eBay