if you haven't heard of it before, it's a senseless phenomenon. Apparently, it is a fad to lay face down with arms at sides in random locations and take pictures of it :)
While I am not advocating this activity, it was pretty entertaining to watch all the youth on mission trip (not just the youth, actually) having fun and being creative with planking mission trip pictures.
And, of course...everyone was so excited when X learned to plank.
More Mission Trip planking pictures here.