A long time ago when I got this game and found how awesome it was, I refused to tell anyone about because I knew Warp would pirate it. I don't care anymore so I will tell:
Looney Tunes Cartoon Conductor is a great rhythm game for DS. It's pretty much* a straight rip of Ouendan, but it's a competent rip and thus a good game. The music is all classical, some of which is matched up with the Looney Tunes ep the song actually appeared in (kill the wabbit, kill the wabbit).
* There is one addition in the form of lines between circles that you have to trace along at the proper speed.