Birthday greeting:
Enter a chat room in PictoChat on the date that you entered as your birthday in the system settings. The message "Happy Birthday! Today is <your name's> birthday!" will appear.

The starting sound of the DS will also change on your birthday.

In-game reset:
Hold L + R + Start + Select during game play in a Nintendo DS game to return to its title screen.

Game Boy Advance in-game reset:
Hold A + B + Start + Select during game play in a Game Boy Advance game to return to its title screen.

Quick Game Boy Advance start:
With both a Game Boy Advance and Nintendo DS game inserted, hold B when turning on the Nintendo DS. It will advance directly to the Game Boy Advance games without the usual warning screens.