Really fast music
From Glitches
From the game Super Mario World for the Super Nintendo
Go to Funky (the last level of the Special Zone) with a Yoshi. Go next to the first green berry but don't eat it. Wait for the timer to get to 99. When the music gets quicker to try to hurry you on, eat the berry, setting the timer above 100. Now, run to the next green berry and wait for the timer to go below 99 and speed up the music again. Eat the berry and go onto the next one. Repeat this for as long as you can, and you'll hear that the music gets pretty crazy.
A Youtube video of the glitch can be found here.
