Deathswitch.com is website that offers an interesting and unique service. From their description:
"Imagine that you die with computer passwords in yur head, leaving coworkers without access to critical files. Imagine that your loved ones cannot find your bank accounts, or that you die with a secret that that you longed to reveal in your lifetime. A deathswitch is an automated system that prompts you for your password to make sure you are still alive. When you do not enter your password for some [user determined] period of time, the system prompts you again several times. With no reply, the computer deduces that you are dead or critically disabled and your pre-scipted mesaages are automatically emailed to those named by you."
Then, on another page, called "Uses", they really lay it out:
"Have the last word in an argument."