Fog, in case you haven’t heard of it, is a fantastic cloud computing library written in Ruby. It provides a unified interface to several popular cloud computing platforms(including Amazon, Rackspace, Linode, and others), making it easy to interact with them from Ruby. It currently supports four types of cloud services: storage, compute, DNS, and CDN. Fog has become very popular lately, and serves as the backbone for Chef’s cloud computing functionality, which is how I first became aware of it.