You can purchase it on Ravelry...
This pattern was designed to use either a skein of gradient yarn or a self-made magic ball and make the most of it by using almost the entire skein.Here are some pictures from the designer.
A magic ball of yarn? Take left over bits of sock yarn and make your own skein of gradient yarn. Think about having a 'Magic Ball' party. Invite your knitting friends, bring your left over sock (fingering weight) yarn and share.
This will also work great with
-Freia Fingering. The yarn does all the colour changing for you
-tosh unicorn tails. These are in stock so you can start right away. I checked on Ravelry and there is a great Boom knit with five colours of unicorn tails - take a look. The knitter even gave the order that she used the colours.
-FiberStory Gradient Kits (coming in September)
I think there might be more than one Magmatic Boom in our booth in Kitchener in September.
More information on the Knitters' Fair will be coming closer to the date but get Saturday, September 12 marked on your calendar.