There are a range of ways that cloud computing can be used to leverage the power of a range of machine to achieve cheaply what you wouldn’t necessarily invest physically in. And to crack PGP or system passwords, you typically just need a lot of machines. So there are a few demonstrations here and here that show off the whole process, including spawning more instances than they typicially want you to 
It’s all based on using ElcomSoft’s Distributed Password Recovery.
Cool!