I've just created a salt state that allows you to install a crypto-currency miner across your salt provisioned boxes. It's only tested on Ubuntu and Debian, but I intend to extend it to Archlinux(there's a lovely aur package that does all the work). Currently I'm mining anoncoins as you have some chance of making tiny amounts of cash and it's exchange rate against Bitcoins isn't so bad but feel free to choose whatever coin you like.
Make literally pennies per day on your salt provisioned servers using a crappy unprofitable CPU-based miner! Yes, this was a labor of love, not profit. The git repo is here.
So when no one is visiting your blog and no one is using your web app at least you can be happy knowing your servers are doing something small towards paying themselves off.