Super Mario Bros. 3 Glitches

Continuous sound from ? Blocks
This glitch continues to play a sound, even after you die. To perform it, go to an area with a ? block that contains an item and an enemy in the same area (works best in world 5's fortress, where two ? blocks lie next to a Thwomp. Then, providing you're Small Mario, basically hit the block, and, at the same time, die. The death theme will be accompanied by an extended note that plays at the start of the item block theme. As soon as the death theme finishes, you'll hear the rest of the item block theme.