This June 3, 2008, file photo shows then Democratic presidential candidate Senator Barack Obama fist bump with his wife Michelle, before speaking at a primary night rally in St Paul, Minnesota. Though the knuckle-tapping action has been around for years, fist bump's place in popular culture was cemented by President Obama and First Lady Michelle Obama when they did it at the convention, and now has earned a spot in the Merriam-Webster Collegiate Dictionary.
