Slottsskogen, Gothenburg

Slottsskogen literally means "the castle forest" and it is clearly one of the best places is Gothenburg. It is located just south of Haga, one of the most trendy places in the city. Whereas most of the ambience in downtown Gothenburg is "mainstream nice", Haga, Linnestaden and Slottsskogen have a very warm and funky feel. The park itself has many memorable spots, ranging from the seal pond (don't miss the feeding at 2:00 pm), the childrens playground (quite a relief if you happen to bring along your kids), a very interesting and fun natural museum and TONS of natural havens.
You will find grassy spots ideal for a picnic, playing with your dog or frisbee or catch up with your reading; rocky hills that are just wonderfull to climb and to warm up to the sun and the best forest tracks to jog.
There are also several activities to do, with the botanical garden just a bridge away (a pretty cute bridge at that too), a mini-golf course, a zoo and if you're lucky enough, you will be able to see (or even participate in) some folk dancing, classical and rock concerts and some of the coolest ethnic music shows.
Of course some of these activities occur only during specific dates or seasons, but even if you miss these events the all-year-round possibilities are well worth the visit.