Anyone know what this wire is and what its used for?

Yes, the Ports are exactly as you describe however. i would assume its a Display to Audio, what its used for its a very good question, its known as VGA/Audio cable. It has multiple uses. 1 use is ( Correct me if i'm wrong ) connecting your computer to your project/HDTV. Just have to know which port goes where. I to have one of these in my house and still refrain from using it for its old tech now that more alternative such as HDMI

Actually, it looks like a Serial to 3.5mm cable due to the 9 pin holes. I know some keyboards have a serial port if I remember correctly.

Its a serial to miniplug - I used to have one for my ti-83 graphing calculator.

+1 to serials, not vga.

VGA is 15 pin (3 rows), and the plug from the monitor is a male plug. EGA is 9 pin, and the plug from the monitor is also a male plug.

This plug is a female plug, 9 pin, which makes it a serial plug. (Serial plugs also came in 25 pin varieties, also female. 25 pin male plugs were used for parallel printers.) Game ports were 15 pin also (2 rows) but I don't recall if they were male or female.

USB did away with most of this nonsense, but the people that make DVI cables have kept it alive with their own brand of nonsense and cables/plugs that aren't compatible from one device to another. Apple has of course created their own brand of nonsense with displayports, mini displayports, and mini-DVI's. At least they had a little bit of sense left and they stayed with standard USB ports.