Want to know a neat trick?
Have you ever wanted to record what you see on your screen? (Like tutorial videos?) Well I learned a trick from the webmaster of Orbithangar where he had run an S-Video cable from the video card out into the in slot of the TV tuner!
Why do you benefit from this?
Well if you configure things right (COUGH COUGH VLC baby!
http://www.videolan.org/vlc/) You can record your video game videos without the performance drop of a software solution. As long as your TV tuner equips itself with onboard MPEG-2 encoding (Like the ATI theater 500) you can just set VLC to record the stream directly to a file and be done with it!
Also you can use VLC to stream out! or whatever else can stream out from the card.