Detour is an app that can be used to take detours when cycling. A live demo can be found here.
Simply, start cycling and whenever you reach an intersection: click somewhere on the screen to see what path to take.
In the following image you can see the first ever detour in Utrecht, Netherlands by Simon Karman and Matt Watson.
Repository
Similar projects
If you like projects like this one you might also be intersted in other game-, and cycling-projects.
Detour (detour)