most of the caching plugins for WordPress will generate static html files, or static html stored in memcached, which can further be written to disk using nginx' fastcgi_cache, or something like varnish.
wp-super-cache. The original* and the best. Saves cached pages to html and html.gz, which allows nginx to serve them straight out (without even compressing them on every request).
* Not actually the original, but definitely the best.
