When the concept was first introduced to me it was presented as a "Functional Global Variable" and I've added my vote to the poll under that category. I must admit, though, that the term "Action Engine" was more appealing to me since it seems much more descriptive of the broader subject (of which Functional Globals are only a subset.)
The term "Functional Global Variable" may be unappealing to some because it seems to emphasize the noun Variable and tack on Global and Functional as adjectives to classify Variable, and the concept really isn't a variable at all. If this describes your view of the term consider this explanation: A "Functional Global Variable" isn't a variable, it's a Function--a Function that can be used as a Global Variable. In this sense the noun is "Function" and "Global Variable" describes the type of function.
Perhaps I can convince all of you to start calling these things "Global Variable Functions".