I've never heard of this place. But, it is a cozy national park, relaxing, forest, some caves around... and it is also a 971 meter high mountain, the highest in Lower Saxony. So obviously there's a ski resort with lifts. Including a gondola! The views are nice, the weather like sunny, and to my luck there was also some fresh snow on the sides of the ski slopes. Can't complain:
Wurmberg is a year-around destination, for hiking, cave visits, and then in the winter skiing. Their ski season runs typically from mid December to late march. Read more about Wurmberg from the lift operator's page, or wikipedia (English, German).