Listmania!
Nintendo DS Games for My Mom
By an Amazon.com customer
Rhythm HeavenRhythm Heaven
Buy new: $27.31 / Used from: $14.99
It looks simple and goofy, without typical time "pressure". I think this would be a hit with my mom.
Trauma Center: Under the Knife 2Trauma Center: Under the Knife 2
Buy new: $59.99 / Used from: $9.98
Just picked this up for her. She loves watching Discovery Health, and she kind of likes icky stuff.
Brain Age: Train Your Brain in Minutes a Day!Brain Age: Train Your Brain in Minutes a Day!
Buy new: $19.20 / Used from: $11.98
This came in a bundle with the DS itself, but she doesn't like it (I don't either, really). The most accessible games (that come unlocked) aren't so much fun, and she's not really interested in learning to play Sudoku. This one is a fail.
Professor Layton and the Curious VillageProfessor Layton and the Curious Village
Buy new: $24.82 / Used from: $16.50
If this is entertaining, I think she could get into it... not sure, though.
Brain ChallengeBrain Challenge
Buy new: $134.89 / Used from: $28.89
This one looks a lot better than Brain Age, because there is more variety in the activities and less chatting.
Flash Focus:  Vision Training in Minutes a DayFlash Focus: Vision Training in Minutes a Day
Buy new: $21.45 / Used from: $7.75
Of the 3 games she currently has (Brain Age, Club House Games, and this), this is the only one she likes so far.
TouchmasterTouchmaster
Buy new: $17.78 / Used from: $15.99
I almost got this instead of Clubhouse Games, and it probably would have been better. However, navigating a lot of menus is a pain in Clubhouse, so it might be the same for her with Touchmaster.
Clubhouse GamesClubhouse Games
Buy new: $16.72 / Used from: $12.29
A bad choice: the music is irritating (and I don't think your can turn it off). It's unclear how to play the games, so it's confusing to select one.
Animal Crossing: Wild WorldAnimal Crossing: Wild World
Buy new: $39.99 / Used from: $22.75
Perhaps she'd like the slower pace of this game.