Offer someone this teaspoon to stir their tea or coffee - as soon as they dip it into the hot liquid, the spoon bends through 90 degrees. The liquid does not need to be boiling - the spoon will also bend if placed under the hot tap.
Part of the handle is made of Nitinol or Shape Memory Metal, which 'remembers' a shape that has been previously set into it. To reset the spoon, just cool it under the cold tap, and straighten it again. The spoon can be used many times, as Nitinol is a very flexible metal.