Today may be President Barack Obama's birthday, but the party has already started. He kicked off the celebrations yesterday in modest style, going out with aides to a hamburger joint on Pennsylvania Avenue.

This was followed by a quick trip to Chicago, the birthplace of his political career. Obama attended two events that focused on campaign fundraising and raised quite a bit of money. One event was a concert, where he was serenaded by various artists, including Jennifer Hudson.

The birthday celebrations are not over. Obama will have a private dinner with his family and close friends on Thursday. It looks like he will also spend the weekend at Camp David with his family, the Huffington Post reported.

The president just signed the new debt law on Tuesday after a grueling battle with Congress. The law passed just in time for the president to enjoy this personal milestone.

"Obviously, I've gotten a little grayer since I took this job, but otherwise I feel pretty good," he told NPR.