From the game Super Mario Bros. 2 for the NES.
This is hard to do, and doesn't work all of the time. Get a potion, and get enough cherries to make a star come out. Throw the potion, and grab the star. Go into sub-space while you are invincible. Right when the Subspace music starts up, exit through the door. If done right, the Subspace music will keep playing.
Submitted by: Brett Notter