Okay! When I was 14, my brother was trying to blackmail me, and I couldn't afford to get grounded. (I had a hot date). He picked up the telephone to call my mom, and I just saw red. I grabbed a butcher knife and winged it at him- it embedded in the wall and cut the phone cord in half. My mom locked all the sharp knives in the trunk of her car for some time after that. I was grounded for the whole summer.
On the plus side, he never tried to blackmail after that.