The joke's on the US White House candidates The two US presidential hopefuls took time off from the tense election campaign to poke fun at one another during a high-profile charity dinner in New York. Two days after the pair traded heated verbal blows in their second televised debate, their exchanges at the formal white-tie event were a more light-hearted affair. "Campaigns can be gruelling, exhausting," said the Republican candidate Mitt Romney. President Obama and I are each very lucky to have one person in our corner, someone who we can lean on and someone who is a comforting presence without whom we wouldn't be able to go another day. I have my beautiful wife Ann. He has Bill Clinton. As some of you may have noticed I had a lot more energy in our second debate. I felt really rested after the nice long nap I had in the first debate," quipped President Barack Obama. It turns out millions of Americans focused in on the second debate who didn't focus in on the first debate. I happen to be one of them. The two face off again in the third and final TV debate in Florida on Monday. It is their last head-to-head chance to win-over floating voters in a tight race a fortnight before the election proper.