Main menu items certainly. The radial menu could do with them, too.
Explaining the difference between background and interstitial music might be helpful here, too.
An interstitial track is played between every background track unless there are no interstitial tracks to play.
I forgot to follow up on this, but main menu items now have tooltips, and the Beepedia exposes further information about topics relevant to each radial menu option :)!
