3026 lines of JavaScript and a Flash Communication Server
Regardless of your opinion on NFL football, check out the incredible work over on the NFL Gamecenter Live site (and hopefully enjoy the Packers getting destroyed).
Not only do the scores update without the page refreshing but it also has audio alerts for the game you are currently watching. I think it is new this week but it scared the pants off me when I heard my computer spring to life as a voice yelled "TOUCHDOWN!". I took the source to seek the Wizard of Oz and it appears to be achieved with a flash swf file connecting for live audio.
This application of web technology works great and it helps me to track the fate of my Bears when all I get to see is Michael Vick having his tantrums because I live in Atlanta.