Shauna Hicks used the term Geneafest in a blog post earlier this week.
My dictionary tells me that a fest is : a special event where people can enjoy a particular activity or thing.
A Geneafest therefore is a special event where people can enjoy genealogy related activities.
I note that Shauna has used the term Geneafest in several blog posts including:
The first use of the word I could find was in this post from Family Tree Magazine in 2010: