The flat area between Münster, Osnabrück, Bielefeld and Hamm is one of the best for a stress-free biking in Germany. Little uphill roads, many street and trails (so-called Pättkes) without traffic, a lot of sightseeing and of course always a guesthouse at hand for lunch and beverages. More information you will find in the following homepages:

http://www.radwandern-muensterland.de/

http://www.radwandern-muensterland.de/oelde/oelde.htm

http://www.radverkehrsnetz.nrw.de/