The K-3 Debug Mode
This is how you enter:
Create 2 files in the root of SD card (Make sure your computer shows the file endings, i.e .txt, .PEF, . JPG etc)
00077760.502
DEVELOP.MOD
Open and add the text [OPEN_DEBUG_MENU] to the first file.
Insert the SD card in slot 1 and turn on the camera without closing the card door.
Enable Debug Mode and press OK. You can now remove the files.
In the Menus, before the C1-menu, you now will find a hidden menu.
Someone entered the Debug Mode has found the way to change the language of the camera menu which was originally locked, here. That must be great! :-D
Update: A more detailed step-by-step instruction with screen captures can be found here (originally in Traditional Chinese, Google Translated to English).