They may not be able to have one in Pennsylvania, but the Kansas City Atheist Coalition created their own Tree of Knowledge and it looks great
The tree’s ornaments are pictures of famous skeptics/atheists who have challenged us to look beyond mindless dogma:
They also “adopted” two families in need, buying gifts for the kids and raising $340 for gift cards for the parents. Such a simple gesture, yet so helpful and powerful. And all without the help of a deity.
(Thanks to Sarah for the link!)