It's actually possible to fly out of the gaming environment in the Stunt course. You need the invincibility cheat for this to work. Go towards the HUGE green half pipe, and go around it to the right, and then make a left so you are travelling behind the huge half pipe, and keep going straight. You will pass a large blue ramp, and then there will be a red ramp to the left. You need to run into that at full speed, and hopefully, you will fly into the air, over the wall!