For a brief time tomorrow, it'll be five presidents at once.

After a morning press conference Barack Obama will head to the White House for the second time as president-elect, to join four of his predecessors for lunch in the Oval Office hosted by the current chief executive, George W. Bush. It's the first such gathering to be held at the White House since 1981.

At her daily briefing today, White House press secretary Dana Perino said that Bush and Obama have been speaking occasionally since their post-election meeting, most recently on New Year's Day. She expects tomorrow's gathering to include some discussion of issues, but predicted they'd focus more on sharing their experiences at 1600 Pennsylvania Ave.

"All of us would love to be flies on the wall and listening to that conversation," she said. "These are leaders who only understand what it's like to be in each others' shoes. And none of us can put ourselves in their shoes. And so I'm sure their conversation will range from everything from personal experiences here."

She expected the challenges of raising children in the White House to come up as well, adding that the Obamas "are doing a great job on that" already. Malia and Sasha, his young daughters, famously began attending classes at the Sidwell School on Monday.

Perino predicted that the scene with five past, present and future presidents and a hungry press corps would be "a little bit of a zoo."