A few weeks ago I was talking with a friend of mine about memcached. I was very curious about what it can do, and it didn't disappoint me (more about memcached).
I've written a wrapper for libmemcached client library and now it's available for Concept. Here you have a code snippet illustrating a simple "hello world" memcached-based application.
It's really simple and you can ease off the database server. As a cool feature, it supports multiple servers, allowing the developer to dynamically add caching servers.