Earlier or later when in Stockholm, you may want to go to the island Djurgården. Because it's nice and green and calm, but more likely because many of Stockholms most famous museums are there. And the amusement park Gröna Lund. Anyway, I suggest you to walk there. You walk along Strandvägen and all the beautifully decorated boats. And some bars and restaurants in summer. And you can enjoy the view from Djurgårdsbron and make some pictures, as everybody does. But if you don't want to walk or if it's raining (which might be the reason why you want to visit a museum), you might want to take a ride on the tramway, called "Spårvagn" in swedish. There is one thing you should know about the ticket. Let me tell you a story about this: In winter after sunset, I wanted to check if the streets on Djurgården are illuminated (they're not, by the way! So if you go there, you'll need a porch!), so I wanted to take the tram at Nybroplan. There's only one tramway in central Stockholm. Number 7 that leads from Sergels torg to Waldemarsudde on Djurgården. When you're lucky, you'll catch one of the historic trams (as seen on the picture), the line is called 7N then. Standing at the tramstation, there was no ticket vending machine, only an explanation that you need a valid ticket (logic) or you can order one by text message. Only that you need an internetconnection on your mobile phone at the station and that you must have registered before. So no chance for both of those points. I had my blue SL-Access-card and some money on it. But there's not even a possibility to validate the card, as you do in the subway. Didn't want to freeze at the station and took the next tramway that arrived. No ticket validation available inside neither. So I thought that if they don't let me pay for the ride, they cannot punish me neither. It was a few days before Christmas, and I was the only one in the tramway, except from a woman with a red Santa hat that was joking around with a kid. So I drove to Waldemarsudde through the dark, nothing happened. The tramway turned around and drove back. Then, the woman with the Santa hat passed by and wanted to see my ticket. I showed her the SL-card, she validated it with her machine and that was it. As easy as that, you only have to know that in advance. Now you do! So always make sure you have enough money on your SL-card. You can buy or top-up the SL-card on every subway or train-station and some newsagent kiosks. All the information about the SL-card and the different tickets can be found here: www.sl.se.
Check out the blog to find more information about Stockholm and what to do and see there. There are different categories (click on the word) such as Gamla stan, Djurgården, Östermalm, food and drinks, free things, museums, sights and photospots, what to do on rainy days and much more!