A head up display in my car so I can avoid bifocals a bit longer.

A teenage mood detector to detect which one of the 3 is most likely to be amenable to doing some chores.

A tazer for when the above doesn't work.

A mobile signal jammer for use in cinemas. Optional damping field to cater people who have paid an absolute fortune to chatter through someone else's rare night out.

A device to find out which of the 48 Christmas tree light bulbs it is that stops them all working!

Intelligent wrapping paper to autowrap those awkward shaped presents in an attractive and unbloke way.