Here is a really cool use trick with the Octatrack. Increase the repeat amount on a Kick and Snare until they oscillate, then add reverb and filters. All on a separate Scene so that you can go back and forth between the original beat and 'singing' Octatrack.

Basically what i did was made a lead sound which later becomes a bass sound out of a track that had Kick and Snare on it and used repeater and cranked it up to that amount that the snare and kick become sonic. Basically they become one long beeep repeating it so fast. Used some filters on a scene and reverb. Crossfader was acting as a filter sweep. Than by changing the repeat speed i played a melody on it. The OT just sang me away :D