How to create a non-rectilinear "stage"

I am trying to create a good old fashioned Pong game, but with a tennis court that recedes slightly in one-point perspective. Right now, the “ball_mc” bounces off the walls of my stage, but I would like to have it bounce off the sides of my court instead.

One of the problems of being a newbie is not knowing how to ask the questions. I am not asking for how to do this - I would like to know what terms I should be googling or looking up in the ActionScript Bible to find out for myself how to do this.

Thanks!