Your Mac is a HDTV PVR
This excellent MacOSXHints.com article explains in detail how to use your firewire equipped mac to record HDTV signals at full resolution for free. All that is needed is a HDTV cable box with FireWire (Since April 1st the FCC requires your Cable company to offer you one), a mac with firewire, NinjaMonkey, and tons of hard drive space. The only downsides are some HDTV signals are encrypted (unplayable), the files can only be played back in VLC, and video at 1920x1080 and 1280x720 (1080i and 720p) takes up huge amounts of drive space.
-CGP fo Life-