Skiforeningen (EN: The Association for the Promotion of Skiing) works for making the woods around Oslo accessible for cross-country skiing and offers therefore a shuttle bus service on weekends in winter, and on Saturdays during autumn.
The destination of the bus is dependent on snow conditions. Most frequently, the bus takes you to Ringkollen, Mylla or Brovoll. The bus always stops at a good point of departure for a long ski tour through the woods towards Oslo, where you can take public transport back home.