Power cable

You can get power (GND and +5V) from the following ports of your PC:

These cables all provide 5 V voltage, don't use them with devices needing a different voltage.
The keyboard port and USB ports should only be used for low power consumption devices, e.g. a circuit board with IC's, transistors and/or other common electronical components. If you have a device that requires significantly more power, e.g. a motor, you should not use the keyboard port or a USB port as these ports are not designed to provide enough power: the device may or may not work but, in the worst case, you may even kill the port or the motherboard. On the other hand, the game port is designed for the motors of force feedback joysticks, therefore, it will have no problems with high power consumption devices.