why not use the data api to access the value of the data-*
attribute
$(".grid-block").click(function () {
$(this).append('<div class="video"><iframe src="//player.vimeo.com/video/' + $(this).data('video') + '?title=0&byline=0&portrait=0&color=bc2026" width="500" height="281" frameborder="0" webkitallowfullscreen mozallowfullscreen allowfullscreen></iframe></div>');
});