How to capture video and audio with a D3100 Nikon Camera?

Okay, so I just got a camera just recently and I wanted to know if there's a way to capture audio and video off a TV with it. For example, say if I wanted to make a movie review or a game review on YouTube.com, and I wanted to capture live footage of it on TV, is it possible with the D3100 Nikon Camera? And if it is, how do you do it? Could someone please explain?

That will not work well as the frame rate for the video will be different from the frame rate from the TV. People use hardware hooked up to the TV for that, not cameras.

You can make a movie of a TV show that is on your TV. Quality may vary. You just put the camera in movie mode, see page 45 of your manual, and start shooting. There's no way to directly capture the video from the TV signal like you can on a recorder.