o__o
I'm a little surprised that you can reply so quickly even while it says you're offline.
Hmmm, DS games...
I think I can forget about recommending TWEWY. That's normally the first answer you get blasted with as soon as you ask for recommendations on the DS anyway.
I don't know, I don't really have that many DS games and since I feel that the DS is on a highway to mediocre shit, just like the Wii, I haven't been all to interested in the DS anymore actually.
However, if you're into fast paced action games (hard ones that require skill and offer a lot of challenge), then I can offer you the Mega Man ZX games (don't be fooled by the name, this is no kids game I can tell you xD).
Otherwise, there's Trace memory and Advance Wars I could think of. You can just look up a few reviews or gameplay videos if you want to get a first impression on them. ^^