The folks over at Seedstudio have created a first for Arduino:  a FPC version!  In the past, it was very common for this material to be used as interconnects between circuit boards in production products.  The flexibility makes it simple to use and the ability to attach components directly saves space.  These are just prototypes, but Seeedstudio is looking for ideas to help move into higher volume production.  Who is going to make the first Arduino watch?