OK... Since I'm "Entertainment Impaired..."

... in the sense that I don't watch movies and have NO idea who these three directors are (as ID'ed in this 3:18 video)...



Could/would someone please explain what the (I'm assuming) humor is here? Coz I really, rilly, don't get it. Yet this lil vid is Numero Uno on today's "ViralVids" list.