What is Missional?

I know I have thrown out the term Missional at various times on this site, with out spending the time to define what it is.  While I have critiqued aspects of it as a movement, and how it has been lived out, I tend to agree with the overall theological foundations and assumptions.

A friend had this video on there blog, and it seems helpful in getting at the heart and core of what a missional church is all about, at least in theory. Freestyle with me, what do you think?