Pop on Top

Step 1. Cut off the top of the paper with a shape in the middle. (it is probably best to start with a circle the first time. (If cutting a shape that is the same on both sides, you might want to fold it first and then cut.)
Step 2. Fold the paper in half.
Step 3. Fold the middle shape down to one side.
Step 4. Fold shape on the other side.
Step 5. Open page and push shape carefully to the inside of the card.
Step 6. Close the card. When you open it, it should pop-up.
Make sure if your card folds bigger than itself when closed, make the background page big enough to cover it when closed.

(Notice how the white background covers the heart that shows when the red card is closed.)

Splash Tip
Cut the shape into other things, animals, etc. or try hanging  things, (stars, spiders, etc.) on the shape with some string, so when it is opened they will dangle.