Well for all you lucky people going to QuakeCon in Dallas, Texas there is some good news. Tribes: Ascend will be playable for the first time by the public there. Tribes: Ascend is being developed by Hi-Rez Studios who have developed the mmo shooter Global Agenda.
Rex COO Todd Harris said:

“QuakeCon has been called the Woodstock of gaming and we’re thrilled to introduce Tribes: Ascend at this show”. “QuakeCon has always delivered exceptional, competitive multiplayer gaming… for free; and that’s our mission with Tribes: Ascend.”

But if you are wondering what Tribes: Ascend is here is a few lines about it:

Tribes: Ascend is a new generation of the online multiplayer shooter, incorporating classic Tribes elements such as fast-paced jetpack enabled combat, skiing, and vehicles, combined with teamwork and strategy.

QuakeCon will be taking place between 4 – 7 August.