If you’ve not seen it already check out a TED talk by Pattie Maes from MIT. The device is essentially a wearable projector and computer that allows people to interact with their external environment by projecting related information about things they are looking at onto the thing they’re looking at. For example, if you pick up a book in a store it could project reader comments or the book website onto the actual book. Equally it could display information about product provenance onto the product in a supermarket. It could even be used to project a watch onto your hand or turn your hand into a fully functioning calculator.

A clickable link appears in the comments below.