My sister, who is gifted, and myself (I might be partially-gifted) like:
~Cooking Mama 1-3 and Gardening Mama

~Animal Crossing

(It's so awesome, I just hope they don't get too attatched to the characters and the move away/they get tired of playing it after a while--long story. But they can also make a new town)
~WarioWare DIY (You really get to make things yourself--great for virtuouso's, artists, game-makers-in-the-making, or anyone who enjoys creating things themselves.

)
~Mario (Super Mario Galaxy 1 and 2, Super Mario)
~Kirby (anyone that comes out

)
~Megaman Battle Network games (only for game boy, but it certain places they have one used game--all of the Megaman games are used, but they mostly work. Some of them don't)
GameStop is the place to go for getting very New--and Used games.

You can return things, we've returned a lot (for example, Diary Girl), and we got at least $140.
Hope this helps!