Time Out says
Every clock-watchers favourite work of art returns to London, this time for a show at Tate Modern. For the unacquainted, Christian Marclay's The Clock (which premiered in 2010) is an ingenious film made up of clips from films showing the time. The cool part (as though that wasn't good enough) is that there's a full 24 hours of it! AND (wait for it) when you watch it, the time you're seeing in the film matches up with the REAL TIME!!!!!
Admittedly, when you put it in words it sounds... oddly underwhelming. But this tick-tocking artwork has a long history of getting viewers super-excited. Go in for five minutes, come out five hours later. Or, head to Tate Modern on 6 October, 3 November or 1 December and stay for all 24 hours. You'll have the time of your life.