When I was living in Japan, I worked at an elementary school. After having lunch, each and every one of the students would take their empty milk cartons and meticulously flatten them. These flattened cartons then all went into the same transparent plastic bag, and I was surprised to see how many it held. A teacher explained to me that this system was utilized because it meant using fewer trash bags, and making less trips to the dumpster. If this system were spread across every school in Japan, the savings would be significant.
Go to any coffee shop in America, and as you look down the silver-lined waste tube thingy, you'll see paper and plastic cups in an ungainly pile, taking up way more space than they ought. However, this café in Korea has a better idea:
Image credit: laxanh
I say it's almost good design, because while it does mitigate the problem, it looks a bit ungainly and unintegrated with the rest of their waste collection system. I also think it can't be easy for the workers to fish the stacks out. But I do think this is a step in the right direction.