We don't have a Nintendo DS (though we have a GameCube)--but PacPix looks pretty freaking cool, and very meta:
"One day a mischievous wizard came up with a mysterious invention called "Ghost Ink." When something is drawn using this ink, it turns into a Ghost. These ghostly tricksters would then jump into pictures and books, to pull pranks and cause havoc around the world. Our hero, Pac-Man, has taken his mighty Magic Pen – the only weapon that can defeat these Ghosts, and locked all the Ghosts inside a book. But before he could turn the Ghosts back into the Ghost Ink, he was also captured within the book! You must now take over Pac-Man’s quest to defeat the mischievous Ghosts. Use the stylus to draw Pac-Man, control his movements to eat up all the Ghosts on the screen. Travel from the lower to the upper screen to collect items and accumulate points. Can you bring peace and quiet back to the world with the Magic Pen?"
Here is a screenshot: