Last week I pulled out the bin of old baby toys in anticipation of my second son (who turns six weeks old today!) soon needing something a little more stimulating than me saying "ah-goo" in his face two hundred times an hour. Now, we're not the biggest fans of toys with on/off switches--and not for any holier-than-thou hippy reasons about the Purity of Play or anything like that but simply because toys with sound are usually annoying as all get-out--but as it happens, one of our family's favorite toys is the Mozart Magic Cube, the whole point of which is to make noise. Go figure.
It's marketed as educational, and I'm sure the main reason the creators chose Mozart songs is so they could sell this to parents who wanted to breed and train little geniuses, but from a more practical standpoint, this is a great toy because (a) kids love it and (b) the music is really lovely and doesn't get old/drive you insane.
The cube plays eight songs using five instruments: harp, French horn, piano, flute, and violin. (Don't get your hopes up about the instrument sounds; they're all electronic, meaning that the "piano" sounds as close to the real thing as my three-year-old's scribbles look like classical oil paintings, but eh, that's not really the point.) By pressing on the pictures of the instruments, you can add or subtract each of them from the songs, which is pretty neat, especially for older kids who can understand more of what's going on with melodies and harmonies and whatnot. Ooh, also, the instrument squares light up in time with the song and according to what instruments are playing, and both my babies have loved watching the flashing lights as much as listening to the music.
Bottom line: Don't buy this because you think it'll make your kid smarter. Buy it because it's a noise toy you won't want to throw on the driveway and back over with your car after having it in your house for only a few months. Great gift. Great hand-me-down/pass-along.