Shoutcast
I set up a Shoutcast server on my racker box so I can listen to my music from home when I'm at work, so I don't need to waste gibbies and gibbies on mp3s on my laptop.  An interesting exercise in RPM building (and rebuilding) and hacking makefiles.  You can enjoy the stream at http://www.superhappykittymeow.com/stream.m3u .  Note: this is music that *I* like, so suck it up if it doesn't tickle your fancy.

While setting this up, I figured the easiest way to stream the music would be to use the source on my fileserver, so I wouldn't have to shuffle files around.  I got it working, but my overall connection was suffering from it -- my poor Time Warner connection was being anally raped and I couldn't do anything else while streaming.  I used Time Warner's online chat to upgrade to their 15mbps package (special online upgrade price of only $5 more than what I'm paying now!), and one modem reset later, nice and zippy.  I hate Time Warner with a burning passion, but I gotta say, this upgrade was pretty painless and I'm pleased with the results.

I have exquisite taste in music, FYI.