[caption id="attachment_8" align="aligncenter" width="300" caption="VGA to S-Video and composite video (and RCA stereo audio??!?!) cable. It uses magic to work."][/caption]
While it's less of an issue now that new TVs can generally accept VGA input, getting a computer's video onto a TV wasn't always easy. While some video cards (both on desktops and more commonly on higher end notebooks) did have composite or S-Video output to use with a TV (in addition to the standard VGA for monitors), most didn't. To get from VGA to composite video or S-Video, you need a scan converter to convert the scan frequency to PAL (for Europe, Australia, etc.) or NTSC (for North America, Japan, etc.) video for a TV.
Scan converters used to be a lot more obscure and more expensive. The most well-known is/was probably the AVerKey line from AVerMedia, which is designed for presentations. Nowadays they run for around $100 new, the same price as the GrandTec branded scan converter available at Radio Shack (which also converts to component video). You can actually get pretty decent no-name scan converters for around $20-$30 from a variety of places online. Generally, they all appear to be the same modeling, sometimes with different branding and/or coloring. A dark greyish blue one appears to be the most common, like this one at Amazon which you can get for around $20 shipped depending on the seller and if you have Amazon Prime. I have one and it does a decent enough job.
But most people don't know that.