In this brief screencast, I show some of the video-glitching the Open Emu NES plugin (for Quartz Composer) can do, resulting in some intriguing unintended consequences. In a nutshell, the video glitches can be physical, i.e., Mario and Luigi can step on the random blocks we're writing to the screen. This opens up interesting possibilities for on-the-fly level-editing, cheats, and tormenting NES sprites.
Get Open Emu at http://openemu.sourceforge.net
Sorry about the poor audio -- I accidentally captured it at a low sample rate.