Rarely has someone coming last in a tournament garnered more headlines than someone coming first (although the Carlton AFL team may be an exception), but this is the fate that has befallen World Champion Magnus Carlsen at the 2015 Norway Chess Tournament. After his sensational loss on time to Veselin Topalov in Round 1, he hasn't been able to take a trick, losing to Fabiano Caruana in Round 2, and Viswanathan Anand in Round 4. The only thing stopping him from 'long castling' in the tournament (slang for going 0-0-0) was a round 3 draw against Anish Giri. But even here Carlsen would not have been happy, missing a tactic (spotted by Kasparov among others) that would have ended the game in his favour.
There are two theories about Carlsen's poor performance. The first is that simply the loss in round 1 (in a totally won position) has thrown him off balance. The second is that he does not perform well in home events, having not won this event in the previous two years, and the Tromso Olympiad was also a poor tournament (by his standards). Basically I think both theories are correct, and have feed into each other, magnifying Carlsen's problems.
Today is a rest day in the tournament, with Round 5 being held tomorrow. Veselin Topalov (Carlsen's round 1 opponent) leads the tournament with 3.5/4, with Hikaru Nakamura in second on 3.
Full coverage (including replayable games) can be found at the tournament website.