DIY Home Theater Speakers

Has anyone ever built their own Home Theater/Audio speakers?

A guy at work and I got to talking about car stereos and he told me he had an Infinity 10DVQ sub that he was not using and sold it to me for $40. My first thought was to integrate it w/the Bose system in our Tahoe, but my wife balked at the idea of a box taking up ANY of the limited carrying room of the Tahoe, so I said, hmmm i wonder if car speakers can be used for home theater because I have a cheap +7y/o Yamana speaker set up for my home theater w.a powered sub that can't handle being driven real hard on really low LFE's.
Anyway, turns out this particular sub in a properly tuned, ported enclosure makes an excellent home theater sub. I researched the precise set up (enclosure volume/port size, length etc) based on the theille/small properties of the sub to tune it to around 22-23 hz. I scavenged the plate amp off the Yamaha sub (it's only about 47watts RMS), and this thing ROCKS the room. My youngest son was watching Nemo, and my wife and I were sitting on the tailgate of my truck parked on the street near our driveway and i could hear the bass. it rattles pictures hanging on the walls of the office directly below it and i can hear it in my bathroom on the furthest end of the house.
The problem now is that the rest of my speakers are tiny and there's a pretty good gap in the 80 to about 120'ish hz range. so now i'm looking into replacing at least the CTR/L/R speakers w/something more substantial (and i may even build them too). you can buy components and get a lot of info from PartsExpress.com.