Power of Attorney
This legal document allows you to appoint a person (your Attorney-in-Fact) to handle your affairs while you are unable to do so yourself.  These documents can be customized to the types of affairs you wish for your Attorney-in-Fact to handle.  The most common type of Power of Attorney is the Durable Power of Attorney.  This type allows for your Power of Attorney to go into effect after your doctor has certified that you are mentally incapacitated.