Slottskogen (The Castle Forest) is the biggest green park of Goteborg's many parks. It is a nice place for all sorts of recreations. For example the park includes a frisbee golf course, a pool with seals and the Natural History Museum, just to mention a few of its possibilities.
Most people come here to take a relaxing stroll along the green lawns and many little lakes. My accomodation was located just at the northern border of the Park, so every morning I could enjoy the view over the park.
Slottskogen is situated southwest of the city centre. The best tram stop is "Linneplatsen" (trams 1, 6), but there are some other tram stops all around the park.
If you're lucky, and I mean truly lucky, you'll perhaps bump into 'En Svensk Tiger' while strolling through Slottsskogen; a large, beautiful park just South-West of the city center which is also home to a small Zoo, (with the most unhappy looking Seals I've ever seen :o( ) an Aviary (the Hyacinth Maccaw's are impressive) The Natural History Museum and the Observatory.
Be warned though: come Fall, Hälge tends to be rather depressive because of the quickly approaching hunting season, so if you're intent on saying 'Hej!', do speak softly and move very slowly when approaching this usually friendly fella. Oh, and no autographs please: he's afraid of pencil's.