I'm pleased to finally release a side-project I've been whittling away at for a few months: Rack::Cache is a piece of Rack middleware that implements most of RFC 2616’s caching features with a basic set of storage options (disk, heap, and memcached) and a configuration system for tweaking cache policy. It should work equally well with any Rack-enabled Ruby web framework and is tested on Ruby 1.8.6 and 1.8.7.
Very cool stuff.