Blind people have difficulty distinguishing the denominations of paper
money, especially in the U.S. where all the banknotes are the same
size and printed on similar paper.   Cell phones with cameras could be
used to take a picture of an individual banknote in real time and send
it to a pattern recognition server, which could quickly return a
verbal description of the bill to the blind person.  A smartphone like
Android could be programmed to make tasks like this effortless, taking
care of details like helping the blind person orient the
camera and banknote for best illumination.

Long term, as Google Street View becomes more complete, and pattern
recognition gets better, a similiar setup could be used with GPS to
help with location, reading signs, etc.   This could also be used in
reverse, using cell phone images to build the Google Street View
database.  In the short term, recognizing bank notes is a much simpler
initial task.   Android could become the platform of choice for
helping a lot of people.

I don't have the time or the programming skills to do this, but
perhaps this message will inspire someone else reading this list.