Autoversicherung writes "Germany has an activated by phone bike rental system across all major cities. At 6 cent a minute quite pricey, germanys famous Chaos Computer Club thought a free ride every now and then couldnt hurt. Optimizing the original system in the process, modifying the blink code to be easier found and changing the logo. About 10% of Berlins bikes are patched already. A detailed description of how they did it, and how the system works."