I think the DS represents a cultural shift with gaming...and therefore a cultural phenomenon.
The DS is a cheap computer device that actually plays really great games (instead of PDAs, Cell phones, and such that play crap games) and has some sophisticated software for adults to learn or to play.
The DS is a fantastic system, and I actually would nominate it for Nintendo's best system ever made.
I even think that Nintendo may be able to recreate the madness of the DS crazy here if they continue to release great adult software to enjoy.
Personally, I hope someone uses the DS and creates a nice scientific caculator program with graphing on the topscreen, which can be brought to the bottom screen for further analysis.
I think this would make a great software application that could even do more things than possible with a regular calculator.
READ: Draw a line on a graph, and have the system calculate a formula for said graph.