Recently an interesting mobile health product was launched: the glucoboy - http://www.glucoboy.com/ . It is designed as an add-on to the Nintendo Gameboy. The basic idea is to combine blood glucose measuring for children and video gaming.
This product shows that an in-depth understanding of the problem domain can create novel interactive products (in this case the idea was conceived by a parent with a direct insight into the problem). For user interface engineering we see again a clear value of contextual enquiry (or at least contextual understanding) combined with a clever utilization of technology.