I do believe that art is everywhere and you don't even have to enter a gallery to get your arty fix. This is especially awesome during beautiful sunny days, when you can take a walk around Metelkova Mesto for example, and be amazed by the vibrant urban art, graffiti, murals and sculptures. If Metelkova is a bit too much for you, why not move away from the concrete and visit the outdoor gallery on Jakopič Promenade in Tivoli Park? It's always open, free and the surrounding trees make the whole experience oh so pretty.
But during colder months you'd might want to stay indoors and I don't blame you for that. So start right in the city centre, follow the big green dot and visit the City Art Gallery. It’s relatively large but unless it’s an opening, it’s not very crowded, so you can totally come here to clear your head.