Oh, yeah, I know exactly what you mean. I still play Brain Age once or twice a week just because it doesn't take long and I like trying to get new records. Triangle math is my favorite. Also, I play the Sudoku anytime I need something to do and don't want to do something too involving like an actual videogame.
As for Nintendogs, I played that game a whole lot but then I reached a point where I asked myself wtf I was doing sending my dog over hurdles and through tubes and haven't played it since. I'll probably never play it again either, but can't bring myself to sell it, it is a pretty good showpiece for nongamers whose interest I wish to pique. I haven't picked up Big Brain Academy yet though, but I probably will.
I think the problem with these non-games is that they are made to be simple and by being simple there just isn't much to see after hours and hours of playing them. Then again the DS has one sort of non-game that I play every freaking day and can't stop and probably never will stop playing Animal Crossing Wild World. So who knows.
