This is a fun little speaker I built over Christmas vacation in 2003. Drivers are Tang Band W3-871S. Internal volume is about .1 cubic feet. Half sized (ie: one hole) cinder blocks were used as the main part of the box. The front and rear baffles are 5/8" MDF, glued on with Liquid Nails. I didn't have a 5/8" router bit at the time, so the roundovers in the picture are actually 5/8" quarter-round pine glued flush to the MDF.
These speakers, despite the humble look, actually sounded very good. Imaging was fantastic, as is generally the case for good single-driver systems, and they were my mainstay computer speakers for years. The only downside to the cinderblock construction was the weight, which is why I eventually took the speakers apart and made new ones with wood cabinets.