I like the virtual scavenger hunt! Thanks for sharing.
We're in the early stages of building out a new intranet on SharePoint ourselves right now. Although it's still newly in the works, and I'm looking to recruit champions early, let them build out their own department sites, and so they feel ownership and pride in promoting the future intranet.
I found in one of our most recent launches, the earlier I can adopt champions, the more ownership users are willing to take to resolve issues and learn the product rather than just forwarding complaints about not understanding the product or that it's "not working."