The Journal Sentinel's headline for this one, "Judge Beer's verdict for underage drinker goes flat on appeal," is at least as good as mine and more descriptive. (Thanks, Scott.)
Judge James Beer did indeed rule in favor of someone caught drinking underage, after that person pointed out that it is not a crime in Wisconsin for an underage person to drink if "accompanied" by a "parent, guardian[,] or spouse who has attained the legal drinking age." The case is amusing beyond the obvious headline possibilities because it involves the definition of "accompanied."
It was undisputed that the drinks were had at a party that the defendant hosted in his dad's garage. Dad was home at the time, and that seems to have been enough for Judge Beer. But the city appealed, and the Wisconsin Court of Appeals did not agree.
In its opinion, the court followed a previous decision in which it had held that in this context, for a parent to "accompany" a child requires some degree of actual supervision, or at least the potential for it. In this case, although Dad was indeed home, he was not in the garage during the party. In fact, "[i]t was not until approximately ten to fifteen minutes [after police arrived] that [defendant's] father appeared on the scene," and it "appeared to the officers that he had been sleeping." Based on those facts, the court held, the trial judge should have rejected the defense and found defendant guilty.
That seems like a reasonable construction of the statute, although you could argue it goes beyond the literal meaning of "accompanied." It's not clear what the defendant argued on appeal; maybe nothing, because he represented himself and the court said that he had failed "to develop any legal argument supported by citations to legal authority" or to the factual record. Maybe his dad accompanied him on the brief, but it might have been a good idea to at least run it by a lawyer. On the other hand, this was probably a loser anyway.
Thus, for future reference, in Wisconsin a parent is not "accompanying" you for party purposes unless he or she is not only present, but conscious. So if your dad is a heavy sleeper and you had planned to roll him into the garage for a sort of "Weekend at Bernie's" scenario, I unfortunately have to advise against it.