Update From OUYA 10/1/2013:
We love XBMC and know you do too so wanted to update you on a recent change. OUYA just learned of some proprietary software contained within the XBMC on OUYA media player app relating to on-device decoding of certain multi-channel audio compression technologies. We need to work with the license holders to enable this functionality so while we work on that (and yes, cost is a major consideration) we have updated the app to remove the proprietary decoding licenses. We hope to have this back soon - and will continue to work on optimizing OUYA for seamless passthrough of multi-channel audio. Thanks for understanding.

This essentially means that until OUYA remedies the situation, you may be experiencing a lot of issues related to sound, video, and XBMC being unstable.