How to create playlist from Up next songs in iTunes?
I haven't found any "one click" method, but these steps do the trick:


Create a new playlist and give it a title. This playlist should now be open in the right sidebar in iTunes 11.
Open the Up Next list via the blue icon to the right of the current song's title.
Click on the first song you want to add to select it.
Shift-click on the last song you want to add.  All songs between and including the first and last should now be highlighted in the Up Next pane.
Click and drag the list into the open playlist.


You'll need to switch to the History view in the Up Next pane and repeat the process of selecting tracks and adding them to your new playlist.  Click "Done" in the playlist sidebar once you've finished adding tracks and putting them in the desired order.