I built a small amplifier for my iPod and mounted it with a cast-off speaker in an old cigar box.
I cleaned up the box and gave it a coat of paste wax. Connectors and controls are mounted on an aluminum panel that is set flush into the back. The 2W amplifier combines left and right stereo channels. The amplifier gain is fixed, volume is controlled by the iPod.
I breadboarded the circuit and the amplifier chip doesn't have a proper heatsink, so it gets pretty toasty. I'm going to see if adding some copper foil is enough. If not, it'll give me the excuse to design a custom circuit board. Though I work as an electrical engineer, I've never done board layout before.
So how does it sound? Pretty good!!!