NYU student Anaid Gomez Ortigoza has designed a heart-sensing iPod peripheral she's dubbed the "Kokoro," or "the heart of things." All you need to do is wear it, and then a Polar heart-rate sensor inside the unit detects your pulse and responds accordingly.
If you're excited, Kokoro will match your excitement with some fast beats. Feeling mellow? Maybe you're in the mood to just sit around and listen to some jazz, which Kokoro can make happen. Buttons on the device allow you to increase or decrease the tempo of the playlist being generated, in case you want to alter your mood.
Click Continue for a video of Kokoro in action.