OK, the scripted part I get. You've got to pay for folks and scripted languages are traditionally cheaper to hire, fine. But the whole "must be event driven" bit sounds like a buzzword requirement, placed in there for no good reason. But hey, who am I to judge, you may actually have a real requirement. In that case the answer is that almost any scripting language can be "event driven" since it's a design pattern and not a feature. Off the top of my head I know there are multiple existing frameworks for python, perl, and PHP that are all event driven. Given my druthers I'd take python for ease of readability and the community, but really, if scripted and event driven are your only two requirements it's hard to see how node is your only option.