Mario Kart

Castlevania (either POR or DOS)

Club House Games 

those three should keep you busy for a while. 

1. Animal Crossing: Wild World

2. Mario Kart DS

3. Castlevania: Portrait of Ruin

4. Castlevania: Dawn of Sorrow

5. New Super Mario Brothers

6. Clubhouse Games

7. Dragon Ball Z: Supersonic Warriors 2

8. Theme Park

9. Super Mario 64 DS

10. Tetris DS 

I live in a house with 2 girls who both have DS's and their favourite games are:

Animal Crossing: Wild World

New Super Mario Brothers (For the Mini Games)

Dr Kawashimas: Brain Training (The One with Sudoku)

Nintendogs (Girls love the cute little puppies)

Mario Kart DS (Great to play against each other in multiplayer or on Wifi) 

I picked it up today, haven't played it much though, what I have played is just as great as the original, only I don't have to sit at the computer desk, I can lay in bed and play it. 

Where did you get it from?

See if you can return it or switch it?