I just found this on Digg. After Sierra fired Dynamix at the height of Tribes 2's popularity, several of the development team of T2 went on to form GarageGames, and programmed the Torque game engine. They're now working on a FREE Tribes-like FPS which is available for download at the link above. As a huge Tribes 2 fan (T2 being the first game that I invested enough time to get "good" at) I am really excited about this. I tried it out for about 15 minutes just now, and even though the graphics aren't great (maybe a little better than Q3 quality), the gameplay is just as good as T2. It's not a finished game yet, but it's finished enough to give an enjoyable gameplay experience, so check it out!