Baby kicks, butterflies or butterfly kicks?

One of pregnancy's simple pleasures is feeling the baby kicks. Not sure whether they really are kicks or an overenthusiastic arm or a head whilst doing laps of the womb. For some mothers waiting for their first baby kick, books and magazines say that they are like a butterfly in your stomach sensation (whatever that would feel like).

Anyway, recently baby has been "kicking" quite a bit. It seems like she is most active when we are about to go to bed. So what is actually going on when the baby is kicking? Is the baby responding to some spicy food or Fanta? According to Ask.com, babies kick in response to the mother's change in position or in response to sounds. They could also kick as they flex and stretch their limbs as they develop.

In another website, they say that classical music such as Vivaldi calms the baby down but babies get agitated by Beethoven. Whilst they can hear and react, their ability to think only begins around the eight month mark.