Reply to Performing with the Kontrol S2: Back up workarounds?

Hey all, this is my first thread on the DJTT community s (very excited to be here!), and it's a question regarding the S2. Since there are no external inputs on the controller, but it is touted as being suitable for semi-professional use, I wanted to ask all the DJs out there that perform live with the Kontrol S2:

What's the best way you've found to implement an emergency backup system (iPod, etc.) when using the S2 on its own?