Pilotwings 64

Warp to New York: in the beginner Class A Rocket Belt fly north to the
city.  When you see a green building, go to the enterance on the side of
it and enter the building.  Follw the path inside to the other side of the
building and your in New York. 

Birdman Stage: To warp to the Birdman stage, fly under the bridge on the
first level. Grab the star and you'll be free as a bird. 

Night on Beginner Course: In the beginner course, you'll find a cave in
front of a chapel on top of thehill. There should be water coming out of
cave, and a sewer grate deep inside. Fly up to the sewer grate and the
game will pause a little and make a wierd sound. The cave should be
darker, when you leave the cave you'll see that it is night time!