Check this out:
Cell Phone Popcorn? - Urban Legend
The original video is part of a viral marketing campaign for Cardo Systems, maker of Bluetooth headsets (you wouldn't want to fry your brains now, would ya?). Looks like it's still working at getting people to believe things that ain't so. Your cell phone does not radiate enough power to pop popcorn (which is
not the same thing as saying it's proven completely safe to have an antenna radiating close to your head).