I find it interesting that certain sounds can calm and intrigue babies. So while browsing a new site for ringtones, I found free bird ringtones. I played the sound and my youngest son immediately took notice to this new lovely song. So I downloaded a couple free bird ringtones to see how he would react.
I played the few I downloaded and he was interested in knowing where the sound was coming from. So now I have programed my cellphone to rotate these ringtones and whenever my phone rings he is quiet. This is especially helpful would I want a few seconds of quiet to answer my phone to see who is calling me. Free and useful, it cannot get better than that.