http://www.ravelry.com/groups/indie-design-gift-a-long gives some more details on this like who and what patterns are being discounted.
Once you buy a pattern you can participate in the Knit-a-long and Crochet-a-long (KAL/CAL). The KAL/CAL lasts for 2 months as there are corresponding threads to the type of pattern you’ll be crafting. Just take for example the Mr. Smith Cowl I talked about in my last post. Now unfortunately, this one is not included in the discount group, but I can still knit it up and hashtag it #giftalong2014neck. I link it in the thread post in the group and then I (and you can be too!) am eligible for a prize. Physical prizes (skeins of yarn) and digital prizes (select patterns). Of course, these projects can only be started between November 13th and December 31st. So get over to Ravelry and check out what patterns are discounted and start crafting!