Do you like to dress up your avatar? Or do you dye your hair blue in real life? The Avatar feature editor normally only allows you to choose ordinary hair colours. However Microsoft have hidden an extra page of 9 colours that are a little more extravagant.
All you need to do to access these extra colours is wait at the My Features screen for 60 seconds. after a minute the hair box will rotate.
If you enter the hair menu and choose a hair style you will now be able to choose one of these 9 colours: