I was shopping on ebay and found this Gigabyte motherboard for uber cheap-and reading the description a bit I figured it was a customer return. They said it worked before, and as soon as I saw that, I bid. It was only after I won that I saw the little text at the bottom: "may or may not work." But I got it in... and the socket turned out to have a bunch of bent pins.
So I spent about half an hour with a lamp over it, and a tiny flathead and a needle bending them back, or at least to where they could contact the CPU. Then I threw in a G520 and gave it a couple of tries.
It worked! So I went ahead and did something I've never really seen anyone else try... touch the exposed Celeron with my finger and see how hot it was. The result was as expected.