In Chapter 2-2 of Super Paper Mario, there's a glitch that freezes the game. Enter the room in the mansion with the falling spikes, and go out without the key (I won't tell you how to get the key... heheheh). Talk to Mimi (the maid) and the game crashes around your ears.
Why it Works Edit
Umm... Bad programming? Because it is only in the United Kingdom version and was recalled because of that.
I accidentally came across this glitch once, but I have honestly no idea who found this.