Crayon Physics is little freeware experimental game from Kloonigames. It's not perfect (some times is really frustratunig) but it's fun. It would be a perfect game for the nintendo DS. Instructions of the game:
"The goal of the game is to move the red ball so that it collects the stars. You can cause the red ball to move by drawing physical objects... With left mouse button you can draw and with right you can remove objects."
