Washington, Aug 4 - It's President Barack Obama's 48th birthday Tuesday, but rather than take a day off and have fun with the family, he will be having lunch with Senate Democrats at the White House.

'Chuck E. Cheese was booked,' White House press secretary Robert Gibbs joked during his daily White House press briefing Monday. Formerly Chuck E. Cheese's Pizza Time Theatre and Chuck E. Cheese's Pizza is a chain of family entertainment centres.

They are likely to discuss health care, the economy, energy legislation and the so-called 'Cash for Clunkers' programme that would provide federal vouchers of up to $4,500 for people to trade in their vehicles for new ones that get better mileage.

Gibbs did not say how Obama would spend the remainder of his day.

Obama kicked off his birthday a few days early with a weekend trip to Camp David. Along with his wife, daughters and mother-in-law, he was joined Saturday by longtime Chicago pals Marty Nesbitt, chairman of the Chicago Housing Authority Board, and physician Eric Whitaker, along with several of the president's childhood friends from Hawaii, according to an administration official cited by the Washington Post.