Idea #7

7. A cell phone that doubles as a Breathalyzer.
Sample scenario: You have had to much to drink and try to make a phone call (well known as drunk dialing) you call that ex girlfriend to tell her exactly what you think of her and the minute you bring the phone up to your head the sensor goes off and immediately turns the phone on mute. When she answers she is unable to hear even one of the names you are calling her.
There would be an automatic override if you are dialing 911 or a taxi company.