You love a good project; you want extensions in your house so you don't have to get a separate line for each of your kids. You want hold music. You want advanced sets. So you want to roll your own home VOIP PBX—that's why there's Asterisk@Home, the open source Linux-based private branch exchange that'll deck your abode out with all sorts of telephony goodness (provided you've got your site networked). Tom's took a look at it, and while you may to have a few things to learn (like what DID routing, trunks, and call queues are, for starters), the Asterisk distro will run on even terribly slow older boxes you've got lying around (they say you can even rock a P 133), and it's apparently very streamlined to install and use. SIP that phone bill, don't guzzle.