A basic unit of measurement of human stupidity. One "duh" is a single unit of stupidity, for example, misplacing your keys would be approximately one duh. Due to the large amounts of stupidity present in the world, more practical units are megaduhs(10^6) or gigaduhs(10^9). Still larger units such as exaduhs(10^18) or yottaduhs(10^24) are more appropriate for measuring stupidity on a global level.
George Bush's tenure would have to be measured in yottaduhs.