A lot has been written in the last week about McCain's ties to Freddy and Fanny after he and his campaign attempted to smear Obama with such ties.
Newsweek has been digging and it appears they may have something. McCain campaign manager Rick Davis is an partner and the Treasurer of lobbying firm Davis Manafort. At Davis' request, Freddie Mac began paying his firm $15k a month in 2006 for which neither Davis nor anyone at his firm did any work. The point of the payments was to buy access to McCain. These payment continued until last month.
The McCain campaign has attempted to deflect criticism by insisting that Davis has received no money from the firm since 2006, but this story has slowly unraveled.
Newsweek: A Freddie Mac Money Trail Catches Up With McCain.