Redis is an advanced key-value store. Like memcached on steroids. Everything is in the RAM and you can theoretically reach 100 000 GET per second with Redis.
My solution below will cache all the HTML output in Redis and display it without the need to load WordPress. I am using Redis instead of Varnish as it is easier to setup and probably also faster.
Interesting way to use Redis for WordPress caching.. I have a couple larger WordPress projects that might be able to benefit from trying this out..