This sample was released before, but didn't have a version that could run on the web without an install.
The new version in the samples pack is almost exactly the same, so I won't go over it again in detail. This post is just to show it off interactively.
When the page loads, press "S" after the text appears. You can then grab the green balls with the mouse to deform the surface. Left-click and drag causes it to deform to the new location and then slowly return; right-click and drag causes it to move to the new shape permanently.