On the Leaseweb Labs blog there's a recent post looking at using the POC framework to work with flexible output caching. The tool makes it easy to create a new object and push cache content into it, automatically caching the data to sources like the file system, a Redis instance or a MongoDB database.
Last year at the Symfony conference in Paris I have heard a really good quote: "There are only two hard things in Computer Science: cache invalidation and naming things" - Phil Karlton. I agree with it and it gave me a boost to keep evolving the concept.
He includes an introduction to the caching features of the framework complete with sample code showing first how to cache to the default file system and a more complex example that uses unique caches and page blacklists. Other features planned for the caching tool include edge-side includes, using Twig for templating and statistics recorded to a database.