Everyone's getting into the biometric controller business -- without actually getting into it. Nintendo's Vitality Sensor caused a lot of blood pressure spikes upon its announcement, but was delayed into oblivion. And don't hold your breath for Ubisoft's Innergy.
The next device to get feedback from your body as you play, and to possibly be canceled before release, comes from Sony. Siliconera found a patent for biometric controllers, and even handheld game systems with sensors built in. They're designed to read your heart rate, electro-muscular data (muscle contractions) and skin conductivity (i.e. moisture).
Rather than putting this technology to use in relaxing, mellow experiences, as the other companies planned, Sony's patent envisions "hardcore" applications, like weapons that increase or decrease in accuracy depending on your stress level, or characters who act more nervous as you grow more agitated.