animating objects in array over time ( mexican wave effect)

Hi,
I’m looking for some kind of build-up/grow effect (the build modifier seems te be too limited). I’m wondering if there is a simple way to animate the object of an array with a certain delay (to achieve the build-up effect). So that when the first object in the array has done its animation the second executes (cfr. mexican wave effect).
I believe you can do nice build-up/grow effect if you could just delay the animation of the instances of an array. Does anybody have any suggestions?
Maybe through Python?