Dividing a Single Object Into 2 Unnconected Objects

I’m trying to simulate a building breaking apart, but I can’t figure out how to make it break. I want to divide a cube into 2 or more separate, unnconected objects that can move independantly of each other.

Fracture addon ? http://wiki.blender.org/index.php/Extensions:2.6/Py/Scripts/Object/Fracture

I guess I could use that and use edit mode to change the shape. I was honestly hoping for something where you could just draw a line across the object and it splits it into 2 objects, but this is good enough.

K for knife tool or boolean modifier and P to separate the mesh.

I can’t find the knife tool. Could you tell me where it is? I tried pressing the spacebar and searching for it, but as soon as I put in “kn” it showed nothing.

Nevermind, figured out how to use knife tool. Thanks a lot!