One of the highlights of Quakecon each year is the keynote talk given by id Software Technical Director John Carmack.
Carmack built the game engines behind Wolfenstein, Doom, Quake, and Rage, among other things. Although the technologies in those game engines are now common, many of them hadn't been implemented in games prior to Carmack's work. He was first with little innovations like real-time texture-mapped true 3D graphics (Quake), Internet-based multiplayer via UDP with movement prediction (QuakeWorld), robust acceleration via consumer 3D graphics chips (GLQuake), real-time shadowing with stencil buffers (Doom 3), and fully unique streaming textures (ET: Quake Wars). Somehow, I didn't even get around to mentioning the tech in Doom or the modding capability that spawned little things like Team Fortress, Counter-Strike, and Valve Software in that list. I think you get the picture anyhow.
Here's this year's super-geeky talk from Carmack, embedded in your browser for easy watching. The clip below is part one of seven, most of which are 30 minutes long. So settle in and watch, if you're able.
Carmack's talk begins at about 15 minutes into this first video, if you want to skip ahead. You can also jump to this YouTube playlist in order to start at the proper spot and watch continuously through all of the clips.
I believe Carmack is giving another speech at Quakecon this year, too. We'll try to link video of that when it's available.