If you have a movie or TV show streamed directly to your laptop from a service such as Netflix or Hulu, there are a number of different ways to display the video on your TV. Most of these methods require specific cables, which shouldn't cost more than $10-20. Avoid expensive "Gold plated" cables, as they don't noticeably improve performance.
Option 1: S-Video Cable. This is the most common, and easiest, option. S-Video cables are cheap and most TV's have a connection for S-Video. This method just requires you to connect your laptop's S-Video port to the one on the TV. Make sure your laptop has an S-Video port before buying a cable. You will also need an audio connection.
Option 2: VGA connection. This is a better option for HDTV's than S-Video, as it provides a high quality connection. The quality of VGA is better than that of S-Video, and the cables are similarly cheap. Note that only HDTV's have a VGA port, so this will not work for ordinary TV's.
Option 3: DVI connection. DVI uses a digital signal, and results in a high-quality signal. The cables are more expensive, however, at around $40-80. In addition, most computers don't have a DVI connection. This is another option that only works for HDTV's.
Option 4: HDMI. This is the highest-fidelity connection available, and will create high quality video. Most computers don't have HDMI connections, so you will likely need a DVI-to-HDMI cable.