4:44 Glitch - Friends of Mineral Town
Watching TV at 4:44 on any day will result in the game being frozen in a loop where the dialog box opens and closes forever. The only way to 'fix' this is to row the direction button in a circle for some time and it will fix the problem.
In the original Japanese version, the "glitch" was not actually a glitch- it had to do with a Japanese cultural belief that the number four means death. It would spam random characters with the number 4 inserted in random places, but eventually stop. The English translators evidently didn't know about this, which caused the glitch in the international release.
See also List of Game Glitches