Good tunes make children happy, and help their IQ as well.

Many of us remember having nursery rhymes sung to us by our mothers when we were young. For centuries, people have always known that children love good tunes, especially if they can learn words to go with them. Recent research has shown that after teaching your children the nursery rhymes, you would be well advised to follow up with folk songs, then the popular classics. The children may discover classical music and enjoy it for the rest of their lives. And it may enhance their ability to learn in other subjects, and even enhance their IQ!.

Classical Music is good for children's brain development and their IQ
Mozart and Beethoven are good for the brain - and that's official. In the United States, anyway. Experts say that good music can stimulate a child's development. In Florida all state-funded pre-schools are now required to play classical music by law, and hospitals have started giving away classical CDs to new mums. 
BBC web site Tuesday, August 17, 1999

 Researchers have found the first evidence that young children who take music lessons show different brain development and improved memory over the course of a year compared to children who do not receive musical training.
The findings, published in the online edition of the journal Brain, show that not only do the brains of musically-trained children respond to music in a different way to those of the untrained children, but also that the training improves their memory as well. After one year the musically trained children performed better in a memory test that is correlated with general intelligence skills such as literacy, verbal memory, visiospatial processing, mathematics and IQ.
ScienceDaily (Sep. 20, 2006)            E Glenn Schellenberg - Music Lessons enhance IQ