Yesterday, while being super-productive in my main project, I stumbled upon (pun intented) thingler and realie, both of which made me say "holy mackerel, this node.js hype looks extra rad!" So a fellow dev and I decided to start a little project to learn this awesome stuff. Maybe sometime in a future in a possible universe I'll post more about that.
Node.js has two major niceties: it brings javascript to the server side thus allowing developers to stop being bilingual -and thus never quite good in one language or the other- and focus on being extra proficient in one language for both server and client sides. And two, is totally asynchronous! non-blocking and truly multiple threaded.
CouchDB, is a schema-less, no-sql, waddayacallit database server: instead of being relational and having tables and structures and whatnot, it stores JSON strings representing objects. Thus, your javascript prowess can even be applied to the database! RAD.
Yet we are used to web frameworks, and we felt that we needed at least a templating system. We're leaning toward express because it allows templates in haml with the hamljs module and, while we were at it, decided to take less, the css with steroids, for a spin with the less.js module. Express feels nice, though the documentation is kinda weird (being that is sometimes inconsistent and totally incomplete).
A comparison of frameworks can be found here and a nice tutorial on node.js and express (though it uses mongodb), here.
You should check node.js out, feels like the future!