The great Peter Elst has done it again.
The TWiT Live Desktop 2.0 is out. It's written in Adobe AIR so it will work on Windows or OS X...
If you don't have AIR already installed the installer will download and install it first, then install the app.
A couple of things you need to know about using it. Double-click on the video to go full-screen. Right-click (or control-click) on the window to get the pop-up menu. From there you can open the Interactive window which has links to chat, the Army, the calendar, and more.