For several years now, I've been a very big fan of Mahjong. I don't play it too often, but I did get my DS so I'd have something to do when waiting at the Dr's offices, waiting for people to arrive at places, etc. This was one of the first games I bought for my DS and I have not been disappointed. Even the timer seems to last forever, so that is helpful for keeping the stress level down. The only downfall I can see is that the "classic" mode is not really the classic mahjong I remember, but it's still tons of fun. Even on easy mode, it's still quite challenging.
This is a great game for someone (like me) who has ADHD and cannot stand sitting still for even short periods of time. This was recently proven when I had to go pick up a friend from the airport. We only had to wait about 15 minutes for his luggage to arrive, but it's difficult for me to stay still and not become agitated for that long with my ADHD. This game helped to keep me calm and able to wait patiently.