Control + F will give you full screen. This is the same for most video viewer programs. If you're not happy with QT then get VLC: http://www.videolan.org/vlc/ (choose nearest mirror site)

I have no idea what rar has to do with video so I'm not surprised you can't find video files wrapped into a rar file.

BTW if you have a video card on your comp with video out, then hook up with your TV!