I'm not quite sure what you mean by which classes are used in games. Do you mean like Actionscript built in classes like Sprite and MovieClip or custom classes made by developers? Can you give an example?
You can use something like <re><code>function spawnCop(xpos:int, ypos:int, look:Class){ //do stuff } spawnCop(random(2000),random(2000), cop1);</code></pre>
Something like that would be used.. If that's what you would talk about..
But you will need to know a bunch of code for a successful overhead game..