I've been planning on releasing many Drupal-modules during the last 4-5 years, but I've always found out that "it's been done", or "it's not good enough" or even "I don't care enough".

Today I feel I have finally something worthwhile to contribute with a performance related project: varnish_tags.

The module may allow great performance increases for large sites by using Varnish very effectively. It it intended to extend/integrate with standard Drupal-modules such as rules, context and some more exotic, such as varnish, context_http_headers and cache_actions. 

It's not done yet though, not even close. Will post later with results.