You can use your bicycle lock for gaming purposes.
Depending on what kind of lock you have, you can lock a handbag, storage box, or cabinet door, for example. If the game requires the use of scissors or another tool, you can lock them onto the radiator. Then just hide the key, e.g. in the ceiling in a cable tray, from where the key must be angled with a stick with a magnet glued to its tip. If you have coded bike lock, you can come up with a story related puzzle that reveals the code (more hints on inventing tasks can be found on the Story page).