They are offering PBwiki Presenter Packs. So, ifyou're giving a presentation about wikis, they will ship you a free PBwiki t-shirt, an easy-to-read PDF about wikis, a Powerpoint with pictures of real PBwiki users, and 3 FREE Gold Premium wikis to give out to your audience.
They have also posted, self proclaimed, the coolest videos in the world. They filmed real educators using PBwiki and asked the questions: what they like, what they can improve, and common concerns. They have posted 7 videos, including:
How do you use PBwiki?
Is PBwiki safe?
How does collaboration work?