Make the cube a "Rigid Body"

Below and to the right of "Pac Man" will be a row of buttons titled "Static, Actor, Ghost, Invisible, and Advanced". Click on the "Static" button which will show a selection of "Object Types" than include "Soft Body", "Rigid Body", and others. Select "Rigid Body".

Our First Animation Test

Now we can start the Blender Game Engine by pressing the 'p' key. When you do so the game engine starts and the cube will gradually accelerate downward and eventually disappear off the bottom of the screen. Hit the "escape" key to stop the game engine. The game engine will stop and the cube will return to its original position.

OK, Ok, not a very exciting animation but at least it is a start.

Build a Flat Surface that the Cube can Bounce on

We need something that the cube can land on. Let's start with another cube. Objects are added to the location that the 3D cursor occupies. Since we want the new cube to be at the intersection of the X, Y, and Z axes we need to make sure the cursor is located at that point. To do so, press Shift+C (hold down the shift key and press the "C" key). Now to add the cube, press the space bar and then select "Add" -> "Mesh" -> "Cube" from the menu that pops up and then right click the mouse. A cube will appear at the intersection of the x, y, and z axes.

To turn the new cube into a flat table like object that can stop the original cube we need to stretch the new cube in the X and Y directions and flatten it in the Z direction. First select the scale munipulator by pressing Ctrl+Space, then on the popup menu select "Scale". Since we are still in the "Front" view you should now see a blue line with a small box at the end coming from the top of the cube and a red line with a small box at the end coming from the right side of the new cube. These small boxes are handles that allow you to scale the cube in either direction. Put the cursor in the ride box, hold the left mouse button down and move the mouse to the right. The cube should stretch in both the positive and negative X directions. Stretch the cube so it is about 10 units in both the positive and negative X directions.

Now change to the "Side" view and stretch the cube about 10 units in the Y directions by clicking and dragging in the small green box. We have now change the cube into an object 20 units in the X and Y direction and 1 unit in the Z directin.

Let's flatten the object by using the blue box at the end of the blue line just above the cube. Left click and hold the mouse button while dragging the blue box down until the object is about 1/10 of a unit high (just estimate it visually). We will now call the new object a "table". Doesn't look like much of a table but it will work for our purposes.