These take pre-created playlists and evenly shuffle them together into a new playlist. You can make a "battle of the bands" playlist, alternating between bands. You can shuffle 5 genres (for example, Jazz-Country-Rock-Folk-Metal) so that every 5th tune is a jazz tune. Perhaps you'd like to alternate between new tunes and old tunes, your wife's favorites and your favorites, etc. These scripts make this easy to do.
(Note: In order to launch this PowerPC-era script on an Intel machine, it must first be opened and then saved using AppleScript Editor, which is located in your /Applications/Utilities/ folder. More information is here.)
Restore each selected track's artwork from an image file stored in its Album folder
Perform various tasks on a selection of playlists; rename, delete, duplicate, merge, more
Rename selected tracks' Song Names with their filenames (minus extension)
Create a text file containing an alphabetical list of chosen tag data
Edit a selection of iTunes tracks' tags in single window
Exports and then re-imports selected tracks' artwork