The home entertainment industry seems convinced that it takes 1000W at .00000001% THD to fill a room with sound. But that's not exactly true and is really only half the story. An efficient speaker system coupled with a small amplifier can take a signal from a media device and make it bigger than your neighbors will let you get away with.
If you are interested in analog electronics and would like to experiment with an audio amplifier you build yourself with discrete components in an evening or two instead of with an IC in 5 minutes, then this is a really fun project. And it just looks way cooler than an LM386 soldered to a 1" piece of perfboard. I've included schematics, detailed step-by-step assembly documentation, a complete parts list, some hacks to get you thinking about how to improve the amplifier, and a thorough description on how it all works.