Does a simple keyframable elastic/spring solution exist?

Once upon a time motion math had the spring script that seemed be the awnser. Motion math went away before I was ready to start thinking about considering getting into scripting animations.

I did a search for this before and found some really neat tricks from Dans site. The most helpful expression I found was his famous jack n the box spring expression:
veloc=5;
amplitude=100;
decay=3.0;
y=amplitude*Math.sin(veloc*time)/Math.exp(decay*time);
scale+[y,y,y]

Not exactally what I was after, for awhile it was enough.
I also work with Cinema 4D and Mograph, they have a delay effector that achieves this keyframeable spring effect with the greatest of ease ... I'm hungy like the wolf.

There has to be a way to make this happen in AE. Does anyone have any clues?