Hrae posts Sprung, yet there's a DS game where you make a girlfriend and you have to kiss the touchscreen in order to make her happy. Then I hear news, that someone actually married their ingame girlfriend.
Let's see...I'm looking at games from here:
http://ds.ign.com/articles/921/921522p8.html
N+ (I haven't play this, but I've played the PC version and it can get difficult, it might frustrate little kids)
Kirby: Canvas Curse (it's different because this isn't a typical Kirby game)
Nintendogs (they might get bored after awhile, but it's still fun)
Pokemon (little kids, like me back in the Game Boy days, love this game, and I still do)
Metroid Prime Hunters (May not be for little kids for the violence)
Tetris DS (I love Tetris)