Eye Toy
This device, similar to a computer webcam, allows games designed for the Eye Toy to be played by moving your body. The camera tracks your movements and translates them into in-game movements.
External Hard Drive
This peripheral is only used for Final Fantasy XI, but allows you to download extra content for the game, as well as optimizing loading times.
Keyboard and Mouse
The keyboard and mouse setup can be used in games such as SOCOM. This feature can only be used on games compatible with a USB keyboard and mouse, so check the back of the box for the words "Keyboard and Mouse Support."
Flash Drive
Many cheat devices for the Playstation 2, such as Codebreaker, allow you to transfer games saves to and from a USB storage device, such as a flash drive.
Charge Devices
The USB port on the Playstation 2 can also be used to charge any device you own, such as an MP3 player or phone, that attaches to your computer's USB port to charge. Keep in mind that this feature will only work when the Playstation 2 is turned on.