Rack::Cache is neato for development, but you're better served using Varnish for production -- it acts as a caching reverse proxy to multiple machines, is insan

Rack::Cache is neato for development, but you're better served using Varnish for production -- it acts as a caching reverse proxy to multiple machines, is insanely fast and battle-tested, it can be configured to serve stale content if the backend becomes unreachable, it supports ESI, and more! And yes, Sinatra & Rack are super cool.