Sometimes I just want to hear more of the same kind of music - like acoustic or heavy rock.
There are at least two projects to analyze music streams and create a "signature" of the music
Mirage as used in banshee http://hop.at/mirage/
moodbar as used in amarok

Any thoughts about building random playlists using one of these fine libraries?

It is now easy to add custom tags in v1.1.x, so it is easy to access the "signature" saved in the tag.
I don't know how easy/hard is the algorithm that create playlists from these "signatures".

My current priority is finishing the few things missing from v1.1.x to finally make a stable release.
I'll probably take a look at this afterward. Though if someone explain to me the playlist-generation algorithm, that could make me want to do it sooner. (no guarantee of course)