Foamcore is truly the world's best "around the house" material for quick projects. An amazing trick not used for simple boxes in the parent post, is to simply score the fold-lines of a box and then fold the foamcore into the shape you desire, instead of cutting all the edges. It makes for very fast and fun crafting.

My favorite activity I ever did with foamcore was to make a to-scale layout of an apartment my wife and I were moving into so that we could experiment with simple to-scale rectangles as stand-ins for furniture to figure out our layout.

What a wonderful material!