A working model of memoristor has been fabricated by a team of engineers at Hewlett-Packard. The memristor is an element in which the magnetic flux is a function of the accumulated electric charge in the device. In otherwords they have the ability to remember the amount of charge that has flowed through them. For the layman it will mean that a fourth passive component ( other than resistor , capacitor and inductor) will be available.
The idea of memoristor was originally proposed by Professor Leon Chua in 1971. There is tremendous potential for these kind of devices. They can make RAM chips that retain data, with smaller chip sizes. Here is a news article on the subject.