I guess they've done these on a few different phones now, but this is the first one I've had. The ringtone sounds just like the interference you hear on any speakers when a GSM phone is nearby and communicating with a tower - and usually it's more pronounced RIGHT before the phone rings - causing people with GSM phones to associate that buzzing with a clairvoyant "My phone's about to ring, hang on a second".
Is it ironic to have that ringtone on a CDMA phone that doesn't cause that interference?
Song is called "Radiation Orchestration" and you can listen to it here (or on your Galaxy Nexus):
Ringtones « Ali Spagnola Music