What happens to leftover campaign donations?

I caught an article today in the Wall Street Journal (always sounds pretentious to start off any form of communication that way, doesn't it?) talking about President-Elect Obama's incoming donations for his inauguration ceremony. I think the whole notion is a bit ridiculous, but I certainly don't mean to single out the incoming administration as all incoming presidents have used their inauguration as a fund raising opportunity.

But anyway, my question is what exactly do they do with leftover campaign donations? Do they manage to spend every single cent of what's donated, planning down to the closing of the polls? Somehow I doubt it, and it's more likely that it's retained by the party or by the campaign, though I did hear that some of Obama's campaign staffers were to receive some somewhat lavish gifts when it was all over.

I guess that's okay, but given how much cash he ended up with and given how much he was able to point to all of the low-dollar donations from "average people," wouldn't it be somewhat patriotic of him and his campaign to hook up some of those folks who donated less than $500 with some of the leftover laptops and other swag from the campaign, to say nothing of at least a partial refund? Just a thought.

Seriously, though, if any of you know the law about surplus campaign funds I'd be curious to know. I've done some research on campaign finance reform but haven't ever seen that come up.