Everybody's tried them at least once. Sitting in front of a screen with a button or a joystick you can make cars go very fast or move strange little green men about as they escape from dangerous enemies. You do it with video games, the electronic toys which are loved by young people and adults alike. Some people prefer space settings, others prehistoric scenes and still others realistic situations in the present. With only a little money an a lot of skill, you can pass several hours absorbed in new and unexpected situations. But, some experts say, excessive use of these screens can be bad for your health. And some very violent video games are now in circulation. So, video games can be bad for you if you don't limit the time you spend in front of the screen or choose intelligent programmes which don't contain violence. Often players forget reality and start to live the adventures of imaginary "heroes". However, there are also educational video games. These can stimulate imagination or help with the study of history, geography and natural sciences.