1. Open kJams
2. Add a song to a singer (thus creating a rotation)
3. Go to Rotation, click play button
4. Pause song (within first 5 seconds or so)
5. Go to Video menu, display rotation
6. Go to Advanced menu, Clear All Tonight Lists
This should throw the error below:
Assert Fail: i_curPlayListP->GetCurPliP() == NULL, in file: '/Users/davec/Developer/depot/kJams/Development/ source/Music/CsongDatabase.cpp' at line 882
Now, it's pretty obvious why this may want to throw an error. The error doesn't result in a crash or hang, as far as I can tell.
How it was discovered: I was tweaking around with Producer, adding a "Who's Singing Next" to some templates, like the iJams one, so I can at least keep the next singer alerted while I'm throwing adverts at them. In order to test the templates, I was adding a song or two to a rotation, going through the above steps (except with my template instead of the Rotation one) and then when I finished testing, clearing the 'Tonight' lists I was dummying up.
Expected behavior - either a) die silently or b) warn user nicely that it may not be a good idea to clear tonight lists while a Rotation is active. (EDIT: or c) some Easter Egg with a

(EDIT: Importance: minor)
There you go, Dave - cheers, mate!
>>Sedge