Ya, its fun...for about 3 days...

User Rating: 7.8 | Brain Age: Train Your Brain in Minutes a Day! DS
...then you stop getting new games added. and to get a new game everyday in the first place, you hav to get on and train at least once a day. after like 3 or 4 days, you start not getting new games for weeks at a time, and once the easy age of 20 is reached, you decide that theres nothing more to be done, and you never play it again. also, it has trouble hearing the word "blue". just because you play the same games over and over doesnt mean that they aren't challenging, theyre pretty fun and if youre good at one you feel good about yourself. also, if a friend has the game, you can always compare brain ages, but only once a day!
theres also a bonus sudoku section that also gets old because the beginner section is super easy, and the intermediate section is super hard (or im just no good at sudoku...thats probably it.) ya...dont buy it, even for $20