Can you trademark a common phrase such as let's roll? The Todd M. Beamer Foundation has been attempting to do just that, so as to prevent anyone from exploiting the words commercially without its approval. Beamer was aboard United Airlines Flight 93, which crashed in Pennsylvania on September 11 following an attempt by passengers to wrest control of the flight from hijackers. He had been on the phone with an air phone operator who heard him say, "Let's roll!" as he and others prepared to act. The Beamer family later publicised the passengers' courageous behaviour, and Beamer's words soon became...