I’m guessing this explains the photo BTW. From the twitpic caption:

President Obama throws a football @soldierfield after the @NATO dinner in Chicago

And from Pres. Obama’s press conference this evening:

abclocal.go.com

President Obama said he “could not have been prouder” of his hometown. He’s sending NATO attendees home with a few mementos.

“We gave each leader a Bean, a small model for them to remember, as well as a football from Soldier Field. Many of them did not know what to do with it,” Obama said. Obama took world leaders down on to the grass of Soldier Field and some visited Millennium Park’s Cloudgate sculpture, commonly referred to as The Bean.

A demonstration? :P

[edit: looks like the Official White House Photographer, Pete Souza took it, whose almost always about snapping up candid photos for the flickr feed]