The Sankt Wendel district in the state of Saarland is a nice spot for relaxation, skating, water sport, and for biking tours.
Sankt Wendel District Map
Cities, Towns & Villages in the Sankt Wendel District
For example, take a tour through the Keltischer Ringwall in Nonnweiler. These are celtic stone walls with a thickness of 4m/13ft and are considered the largest fortification of the Celts in Europe. They offer sightseeing tours.
Another sweet spot is Tholey and its Hofgut Imsbach as well as the Johann-Adams-Mühle. The former was a fortress in the Third Reich, the latter is a historical mill which was nicely restored and still has a 200 years old oven plus a picturesque restaurant.
Then there is Sankt Wendel, a 1,500+ year old town with historical buildings, invitations to events and celebrations, and a couple museums and gardens.
Last but not least, you should go visit the Bostalsee (southwest of Nohfelden), a popular lake which is the largest in the Sankt Wendel district, providing you with lots of opportunities for water sports and camping.