Presidential crackups: A photo retrospective of laughing leaders

With rising approval ratings and a lackluster field of Republican challengers, President Obama has plenty to be happy about. And he's hardly the first American president to guffaw on camera

From the devastating BP oil spill to the floundering economy to the Democrats' midterm "shellacking," there wasn't a lot for President Obama to smile about during his first two years in office. But things are looking up for the president these days. Osama bin Laden is dead, the president's personal approval ratings are as high as 72 percent, and big-name Republicans like Mike Huckabee and Donald Trump have opted out of the 2012 race. Through it all, Obama, like many U.S. presidents before him, has found time for a good laugh. Here, a look at some notable executive acts of laughter: