This might be old news to many people, but first time I've seen it and I thought it was interesting - one of Google's original racks.

Made up from commodity Pentium II PCs (appear to be stock Intel coolers, Intel NICs, SuperMicro boards, and I think they're DeskStar hard drives), squashed into a rack with corkboard stopping them shorting out 😀

I saw this is in the Science Museum in London today. Wonder what someone would pay for this on eBay!