Both candidates in Minnesota are challenging ballots as their recount moves forward, but it looks like the Republican candidate, Norm Coleman, is going slightly more crazy at this time.
From fivethirtyeight.com (Nate Silver):
Now, the Coleman campaign isn't being devious or anything like that; they're simply exploiting a flawed system and trying to win a spin war. But news organizations should recognize that -- as of about Friday afternoon when the number of challenges skyrocketed -- the entire first phase of the recount process essentially became a spin war. The running totals being reported by the Star Tribune and the Secretary of State are at this point fairly meaningless, and should be denoted as such; we aren't likely to learn very much more about the ultimate winner of the recount until the state canvassing board convenes in December.