Orbs can be purchased with Forum Gold under the Settings section of your account:
You will see that there are 7 different orbs for sale. Also, you will see the price of each orb, followed by a preview of what the orb would look like. However, not all orbs look the same, depending on what browser you use.
The preview of the orb will show you how the orb will look on the specific browser you are using.Opera:Firefox:Internet Explorer:Safari:
As you can see, Internet Explorer shows more of a "glowing" effect from the orb, while Firefox and Opera appear as more of a "shadow". Unfortunately, you cannot choose how your orb will look for different browsers, because of the way each browser is coded.Orb of the Rainbow
The Orb of the Rainbow is a very special orb. It is sold for a much higher price than the other orbs, because of its unique powers. With the rainbow orb, you can create your own colors for the text and the glow of your orb at any time you wish. As you have probably noticed with the other orbs, you are restricted to one text color and one glow color. With the Orb of the Rainbow, you are given the power to choose exactly which colors your orb will have, to decorate your name as you wish. As you can see, there are text boxes where you can enter the specific code to make the color that is right for you. You can also click on the small color picker icons to the right of the fields to select your color.