iTween.cs -

http://code.google.com/p/itween/source/browse/trunk/com/pixelplacement/i
tween/iTween.cs
http://itween.pixelplacement.com/index.php

Copyright (c) 2011 Bob Berkebile (pixelplacment)

iTween is an interpolation system that takes one value and animates it
to another over a given amount of time.