I digitized a good chunk of the Dutch broadcast archive using a custom built cluster of PCs and a tower of CD readers. We must have processed many thousands of CDs and entered all the meta data and submitted it to CDDB before the Gracenote acquisition. It was pretty interesting to see a whole delivery van full of CD arrive and to see them go away again a week or two later + a crate of harddrives.

The second version of the cluster looked like this:

https://www.clustercompute.com/

The first (of which I have no pictures) was just 10 whitebox PCs.