From CBS News' Maria Gavrilovic:
(BEAVER, PA.) - Less than a week after the debut of the Obama-Biden ticket, the Democratic nominees appeared to be the best of friends on their official first day of campaigning.
From the moment they met up on the tarmac in Denver, they laughed and gave each other big pats on the back, while their wives embraced each other. Their campaign stops consisted of a tour at a biodiesel company and ice cream with voters.
"I may have vices but this is my biggest one," Biden told the Obamas as he ordered two large scoops of chocolate and vanilla ice cream.
"I ran for vice president just so I could get ice cream."
The Bidens and Obamas also met with the head coach of the Pittsburgh Steelers, Mike Tomlin. "Hey coach, I'm Joe Biden. I'm second string," Biden joked.
The lovefest continued into the night, when Biden and Obama hosted a campaign rally which drew a crowd of over 8,000 people.
"America is ready to get back up! And this is the man that's going to get 'em back up!," Biden shouted as Obama looked on.
Obama explained that he chose Biden as his running mate because he didn't grow up with a "silver spoon" in his mouth.
"[He is] somebody who came up the hard way. Somebody who never forgot where he came from," Obama explained.
But despite the carefree mood, the ticket was faced with their first challenge today when they had to respond to John McCain's pick for vice president.
Although Obama was the only one who spoke to cameras, both candidates called Gov. Sarah Palin, R-Alaska, and issued subsequent statements. Aides said Obama congratulated Palin and said he looked forward to seeing her on the campaign trail while Biden's aides said he told her he looks forward to getting to know her.
Obama and Biden will campaign together through Sunday.