Muji has released a set of 100% recycled cardboard box speakers. They are very portable, simply because the boxes can collapse, and this is how they are shipped to you, flat packed in a bag. The fun part, according to Muji, is putting them together, you can even put them in other boxes, or paint and decorate these for your own personal look. I could not even imagine how these would sound, with sound escaping from corners and cracks, audiophiles stay clear.
They measure 3.25-inches square and will run you US $42 a pair.