From the game Metroid Prime for the Nintendo Gamecube
Go to Ice Ruins East and kill all the Icesickle creatures. Go to the frozen waterfall and lock onto air. Then, jump onto the waterfall (holding up on the control stick the whole time so as not to fall off), then jump backwards while still locked and jump to the left. If done right you should be on top of the building. Go towards the gap between the two buildings where the waterfall is, then look at the fan-type object on top of the building behind you and lock onto it. Jump towards it (note this whole thing is very tricky), and you should end up on top of that building part. Jump across the gap to the other building, and into a glitch world. You can come back inside the walls of the game from the outside part, but the game seems to try and stop you and you'll start to sink and eventually won't be able to move and will get stuck.
Submitted by: Glitched Symbols