Audioscrobbler / Last.fm
Like the sad geek I am I've wanted to use Audioscrobbler (now Last.fm) for some time now, but I don't really use a media player on a computer to listen to music, but a hifi with real CDs. This poses a bit of a problem as there isn't a way of uploading playback data without using a media player... until now that is.
With a little Python and MusicBrainz magic, and an Audioscrobbler upload implementation by the mighty Matt Biddulph, cdscrobbler can submit an album as if you just played it from either a MusicBrainz album ID or by reading the CD from your computer's CD-ROM drive.
I've been using it for a few weeks now and it's been working great, so I'm releasing it to the world. At the moment it's only available via Bazaar from http://burtonini.com/arch/cdscrobbler--MAIN--0/, but I'll make tarballs at some point I'm sure.
NP: Vertigo, Groove Armada