Once you get 120 stars, go to any level and do a tripple jump. You will see stars trail behind Mario. This is useful. Now, say you tripple jump off of something high and you are afraid of getting squashed, well don't be. You will land with a bounce and stand up and be unharmed! Submitted by A.J. Prack
When you have 120 stars go to level 4 (the snow level), then go to the big penguin race and you will see that the penguin is very overweight! This code was given by Stuart Spence.
Once you get all 120 stars, go to the cannon outside and shoot yourself up to the top of the roof. If you talk to Yoshi, he will give you 100 lives. You will also have an improved triple jump!