Become big Mario, get a Yoshi, and go through Chocolate Island 3 until you get close to the end where there's one goal above you and one to the far right. I find this glitch is easiest to do as Cape Mario and Blue Yoshi because it lets you get through the level very quickly with the koopas all over the place to use. Now, stand directly under the goal above. Jump up and then push A to jump off Yoshi. If you time it so that this double jump goes high, Mario will hit the goal above. He will fall from the goal and land back on the lower platform with Yoshi. He will continue to walk to the right in the winning point-counting mode. However, that platform is pretty short and Mario will fall down after walking on it for a bit and you'll die, losing a life, even though you were already through the goal.