The vintage 50's Aperture Science Innovators Cube paper craft from PORTAL 2. This is the third cube I have built and by far the easiest and quickest. The reason is it doesn't have all those bumpers that have to be folded.
I used the same techniques to build this one, but instead of gluing the actual cube onto bristol paper, I glued it onto brown cardboard that's used as the back cover of a basic college ruled notebook. Amazingly that, and the basic cardboard I glued on the inside, made this cube heavier than the other two I built.
This cube took me about four days to build, because of the process of making it strong. Thought I'd let you all know.
Here's the link to where I got the model: [link]