As of right now, it looks like a Ted Cruz blowout, although Cruz will likely "only" net 30 delegates or so, because Trump is likely to win a couple of Congressional districts. That said, Cruz has massively outperformed polling, beating Trump by around 15 points (instead of the projected 5).
This caps off a long and troubled week for Trump, in which he saw his campaign manager charged with battery, and repeatedly and damagingly fumbled taking a stance on abortion; his promise that, "Wisconsin – it's going to be such a big surprise on Tuesday!" has certainly turned out to be true (a rare example of Trump being right) - no one expected him to get steamrolled by such a large margin, including Trump himself, who wrapped up the night sulking in Trump tower, while releasing a delusional statement:
Donald J. Trump withstood the onslaught of the establishment yet again. Lyin’ Ted Cruz had the Governor of Wisconsin, many conservative talk radio show hosts, and the entire party apparatus behind him. Not only was he propelled by the anti-Trump Super PAC’s spending countless millions of dollars on false advertising against Mr. Trump, but he was coordinating `with his own Super PAC’s (which is illegal) who totally control him. Ted Cruz is worse than a puppet— he is a Trojan horse, being used by the party bosses attempting to steal the nomination from Mr. Trump. We have total confidence that Mr. Trump will go on to win in New York, where he holds a substantial lead in all the polls, and beyond. Mr. Trump is the only candidate who can secure the delegates needed to win the Republican nomination and ultimately defeat Hillary Clinton, or whomever is the Democratic nominee, in order to Make America Great Again.