One simple and incredibly fun way to use return tracks with the crossfader is for simple beat juggling. To do this, throw a Simple Delay on the return track set up like this:

Picture 7
All you’re doing is using the delay as an 1/8 note offset, so every time you flip the crossfader, the signal is 1/8 note behind the original audio. This allows you to create all sorts of cool fills and variations, just by moving the crossfader back and forth.