A while back, there was a series of DVDs designed to stimulate young children's minds. If memory serves me right, the manufacturers eventually had to pay a huge settlement because the videos did no such thing.

Oh, I guess they had some effect. But not much more than those cat food commercials that are supposed to get your cat's attention when they come on. Doesn't work with either of my cats [they may be color-blind].

I'm not sure if this will work any better than the commercials, no less the DVDs. But if your child seems to respond to the big beats, maybe this will have an effect:
[WaxandHerbalT/YouTube]