A talented fellow tech writer here at Google has created documentation that describes how you can create time-animated buildings in KML. As an example, she uses is the now famous London Eye ferris wheel animation (see image).
Outside of this documentation, other animation examples include the rising sea level and arctic ice melting models. Frank Taylor highlights many other animations on his blog.
Once you have downloaded such animations, you can display them in Google Earth by using the time slider. This KML content is defined along a time span. Changes animate as you move the time slider. Learn about using the time slider.