Instructables contributor goldlego of Creations by Cal created a clever greeting card that looks like an old loading window with animation when the card is removed from its envelope. He has step-by-step instructions on Instructables.
This is an awesome hand-made “Loading Message” card and it is super easy to make! Watch as you pull the card out from the envelope the bars will actually “load”! This card isn’t just great for techies, its great for everyone!
images via Instructables