This is a very amazing trick. you can switched off your friend's mobile by a single message...
1. Keep any Multimedia Cell phone.
2. Type 51 or 79 inverted Commas like this ( ' )
3. Now send it to your friends cell phone.when they open this message, then their mobile automatically Switched Off.
Tips:- You can add your own words at the first of the message like you are too stupid.
This trick works only on specified nokia mobile like nokia 1600.