Simple simple simple. I salvaged some 1x4 plywood planks that were broken from around my work, cut the broken ends off and cut the four odd lengths into as many 1' lengths as I could get. I put together four of them together as a frame, then screwed the extra ones onto the bottom, cutting the last one thin enough to not hang off the edge.
To finish it I went with a little rasping and sanding to smooth the edges and mask slightly unsquare edges and used a propane torch to add some age to the box, burn off the little flaky bits, and seal the wood a little. It's also a decent faux-aging since it already looks like something they don't make like that anymore. I dunno what I'm planning to do with the bugger. Any ideas? It's really strong, I guess it would make a good soapbox to speak from.