well, I WAS gonna be Chell, but that never worked out... so this is I guess, the only awesome part of my costume ^_^; (lol I looked like an aperture baker!)
I seemed to wow my class mates at school, I was quite happy ;D it turns out my high school annex makes a great backdrop!
I started out with some pizza boxes. I spray painted that cube dark gray, then I enlarged the papercraft corners of the companion cube to fit mine. I used cardstock for that, and glued them on (after spray painting). I traced a plate for the middle, and guessed on the inbetwen parts, and I have to say it turned out quite well ^_^ Looks like I have a new table for some papercrafts!