The Museum of Contemporary Art Metelkova is the newer contemporary-art branch of Ljubljana's national modern-art museum network, set in the former military barracks complex near Metelkova. It focuses on postwar and contemporary work from Slovenia and the wider region, with exhibitions that sit naturally beside the alternative cultural life around the barracks.
It is a good stop if you want Ljubljana's art scene beyond the old-town circuit. Combined tickets are usually available with the Museum of Modern Art.