Earlier this week he made an appearance at the Sohn Conference, a conference and fund raiser for research into paediatric cancer. There he played a 3 board blindfold simul in front of a large crowd, while GM Maurice Ashley provided commentary. To keep it short, each player had 9 minutes on the clock, effectively giving Carlsen 3 minutes per game.
Of course blind fold simuls had been done before, as far back as 1783 when Philidor stunned Paris by playing 3 unsighted games at once. And while Carlsen's effort falls far short of the record of 52 games by FM Marc Lang, this was played under slightly more exacting conditions. As a clock simul the players could move at any time, meaning Carlsen had to "randomly access" each position (normally in simuls players move in order). On the other hand his opponents did not have the luxury of waiting while he made a circuit of the (virtual room) meaning their clocks were running down as well. In the end this seemed to help Magnus more than his opponent as he ended up ahead on the clock in some of the games, resulting in resignations from his opponents.
A brief 3 minute video of the action is here, while you can find the full version on youtube.