I kind of like the "genius" playlist feature in the new iTunes, so I attempted to do something similar for J. River's Media Center (my music manager of choice at the moment).
The idea behind iTunes "genius" feature is to scour your music database and queue up tracks similar to the one you are currently listening to. How well it does this is debatable. iTunes seems to cook up it's "similarity" data based on the listening and purchasing habits of it's users. Interestingly, if everyone's listening habits were completely eclectic, and if they always kept their player on random, there would be nothing to go on. Fortunately, this isn't the case.
Sometimes these genius playlists are spot on, other times they are wildly divergent. Either way it's kind of fun.
Unfortunately iTunes doesn't make their "genius" info available via web services, so my plugin leverages Last FM's web services instead, which will give you a list of similar tracks for any track, as well as a list of similar artists. Once again, results vary.
Here's an example:
>>> Looking up "When We Get Famous" by Math And Physics Club
Merging with current Playlist
Found 149 Similar tracks according to Last FM
Found track: Mars by The Lucksmiths
Found track: Young and Dumb by The Lucksmiths
Found track: Get It Right by The Fairways
Found track: Twee by Tullycraft
Found track: Leaders of the New School by Tullycraft
Found track: Emblematic by Pipas
Found track: Run Run Run by Pipas
Found track: Popkiss by Blueboy
Found track: Talulah Gosh by Talulah Gosh
Found track: One Two Three Four by Acid House Kings
Found track: Springtime Sunshine by The Shermans
... and so on.
Here's a screen shot:
I've tried this on J. River Media Center versions 12 and 13, and also on Jukebox. Here's the installer:
J. River SmartAlec Plugin v. 0.1
Here's the source code as well, in case anyone wants to poke around. I did this in MS's Visual C# Express Edition. If you do anything cool or useful please send me a copy. The project uses Martin Lottering's CheckBoxComboBox control which can be found on CodeProject, as well as an XML-RPC wrapper which can be found here.