For the last few months I have been living and working in Stockholm, Sweden. It is a genuinely pretty city with a unique character. Don't assume that if you have been to northern Europe that you will understand the Swedish culture, it is distinctly different here in the Nordics.
The city it's self offers a huge variety of activities as well as the some what more unique ability to travel 15KM and feel like you have really stepped into the wilderness.
If you don't know this the Swedish people love outdoor activities and the city offers a surprising number you can try relatively easily. One area well worth checking out is Smedsuddsbadet on Kungsholmen.
Here you can go to a bowls bar or sit on a man made beach, taking a wind surfing lesson or even do yoga sitting on a SUP board; this area has something for everyone.
Out of Town - Hiking / Mountain Biking
A little further out of town there are some really great spots like Kalltorp where you can cycle, swim and enjoy nature. You can hire a bike from Bike Sweden in the centre of the Stockholm and in an hour be swimming in a lake (all be it a cool dip even during the summer). For the extreme mountain bikers out there the technical sections of the yellow trail on the northern hill around the lake are far beyond my skill (and ability on a hard tail).
Top Things To Do In Stockholm
Saturday Blues Jam at Stampen
Brian Kramar's International Blues Jam at Stampen every Saturday from 14:00 until 18:00 can be a really fun and free way to spend your Saturday afternoon. The players are typically local but occasionally you have guest musicians who really stand out. There is a really friendly atmosphere where everyone, including children are welcome: quite often there are musicians in their teens joining in.
Selma City Spa on the Rooftop of Clarion Sign Hotel
If you are in need of a sauna, spa, or a fun pool to hang out in you should definitely check out the Selma City Spa at the Clarion Sign hotel near Centralen T-Ban. They have a selection of treatments including massage which you can follow with a sauna and swim in the outdoor heated pool. Even if it is raining you can still relax in the heated pool, it is 35'C so even if it is cold outside you will have a great view of the city from the pool.
Walk Along the Djurgardsbrunn Canal
This was one of my favourite walks in Stockholm. The view of the city from the north side of the canal is really exceptional on a sunny day. You can walk along one shore then back on the other. It is a very picturesque area.
Take the Archipelago Boat Trip
Stockholm city is a place dominated by islands and canals and one of the must do activities is to take the archipelago boat tour which sets off in the morning and the afternoon during the summer (I assume it doesn't run in the winter when the sea is frozen... ). The trip takes a few hours and gives you a glimpse into the idyllic mix of nature and space that make the Swedish summer house such an established tradition for man Swedes.