The liquid does not need to be boiling - the spoon will also bend if placed under the hot tap.Link
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.
Mark Frauenfelder is the founder of Boing Boing and the editor-in-chief of MAKE and Cool Tools. Twitter: @frauenfelder. His new book is Maker Dad: Lunch Box Guitars, Antigravity Jars, and 22 Other Incredibly Cool Father-Daughter DIY Projects