The one thing that most people know about antimatter is that, if brought into contact with normal matter, they will annihilate each other. Although making bombs from antimatter is in the realm of science fiction, small scale annihilations are set up and studied by particle physicists. Annihilation reactions are especially useful to physicists because they are very efficient - all the energy put in is released and is then available for the production of more particles (this happens almost instantaneously).
At LEP at CERN electron and positron beams are put on a collision course and the products of the annihilation reactions are studied, allowing precise testing of the standard model, and a glimpse of the conditions in the early Universe.
