In the pre-game lobby of any game you are in bases and you can run around in your own base. If that's not enough for you then try this: hit "A" to bring up the game details. Make sure the camera is directly behind you and start running towards the window. Now hit "B" to cancel the window just before you run into the rail and lose your momentum. It's tricky, but if you timed it right, you can run through the rail and window and into space. If you get stuck in the rail just keep running toward space and turn left and right until you go through the wall. It doesn't help you win but it is a lot of fun!