It may seem too futuristic now, but one day quantum computers might come along and make yours look like a solar powered calculator. Computers work by manipulating pieces of information called bits that come in one of two forms: one or zero. String enough bits together and computers can solve some pretty complicated problems.
The idea behind quantum physics is that subatomic particles can exist in more than one state at the same time. So quantum bits that consist of atoms wouldn't be limited to one state: they could be a one or a zero or both simultaneously or something in between.
Basically, a quantum computer reading a bunch of atomic bits could process all of these possibilities and perform a million calculations at once, while old computers are forced to do them one at a time.
Sadly, it'll be years before we've developed the technology to build commercial quantum computers. And even then, chances are they won't end up on your desktop.
In order to work, quantum computers will have to function in very low temperatures. The kind of computing power we're talking about will most probably be used for factoring large numbers and encoding and decoding information.