There's a file that's been circulating widely by email which suggests some pseudoetymology for several phrases. Several more respectable websites devoted to etymology have panned this letter, partially or completely refuting each and every etymology claimed.

One copy of it reads like this, in part:

Do you ever wonder where some of the everyday expressions we use come from? Here's a chilling tale that takes us back to the dark days of the 16th century in England. Being a small country with a high mortality rate they began to run out of burial sites. They began to dig up the old graves to re-use the same grave site. When they opened the coffins they dug up they found many of them had scratch marks and inner linings torn out. They realized that they had been burying people alive! The solution....they decided to tie a string onto the wrist of the recently departed, lead it through a small hole in the coffin, up through the ground and tie it to a bell. Someone would be posted out in the graveyard through the entire night to listen for the bells. Thus you have a watchman on the "graveyard shift" listening for a "dead ringer" who would then be "saved by the bell."