I enjoy exploring new cities by bike--and Berlin is certainly one city that is great for cycling. It is flat, bike-friendly, and there are numerous options for renting a bicycle for a few hours or a day. On a recent visit, my husband and I tried Call a Bike, Deutsche Bahn's bike rental system, choosing from a long line of bright red bikes at Alexanderplatz. Comfortable, well-maintained and easy to ride--the bikes also came with locks, handy for our frequent restaurant stops.
Call a Bike is offered available in a number of cities across the country, as well as at Deutsche Bahn's ICE stations. DB also has cycle-sharing arrangements with other rental-bike operators in Kassel and Hamburg.
Bicycles can be reserved via mobile phone, after registering on the DB Call a Bike app (currently available only in German). Day rates range from a maximum of 9.00 Euro for students and BahnCard holders to 15.00 Euro for everyone else. From Aachen to Warnemünde and a host of places in between, the service is a great supplement to long-distance train travel in Germany.