Anyone who saw Native Instruments' recent promo video with Dub FX (above) will be ahead of the game with this one. If the Freemixer does away with records, the Freestyler does away with pre-recorded music altogether.
If your DJ software includes a function that enables you to record in with a microphone and treat this sample like any other track, this paves the way for the completely Foley mix set. If you don't have the beatboxing skills to come up with solid rhythms etc, you could mix pre-made beats and bass, and add your own custom melodies, vocal hooks and so on.
Surprisingly complex sounds can be created by layering recordings on top of each other, but if you don't want to go the whole hog, DJ as normal and bring in extra vocal shots on the remaining two decks as you go. It’s probably worth practising a few times at home before dropping these into a live performance though!