A source close to the McCain campaign tells me that online fundraising is up 500 percent this week over the previous weekly average -- a reflection of the Arizona Senator's lift in the polls and some key endorsements he garnered in recent days, such as that of the New Hampshire Union Leader.

"We had the Union Leader, and we had a kick-ass six day trip," the source says.

In another positive development, the source says there's been a rise in the number of people calling the campaign to volunteer their services. Interestingly, the callers are volunteering on the strength of having seen the mailer that McCain recently dropped in New Hampshire telling of the Christmas inspiration he felt during his days in captivity as a war prisoner in Vietnam:

"It's incredible," says the source. "People who see the mailing are calling in, saying they want to join."

At any rate, such developments are producing something approaching good cheer in the McCain camp.

Late Update: One necessary caveat: As Josh says, "big percentage jumps are a lot easier to put together when you're coming back from near zero."