Lazy loads videos as you scroll. Place the iframe src in a "data-embed" attribute. Use with jQuery.

lazy_video_loading.js

$(document).ready(function(){
    var vid_links = $('a.video');
    function showVideos(){
        if (!vid_links.length) return;
        var window_bottom = $(window).scrollTop() + $(window).height() + 500;
        vid_links.each(function(){
            var link = $(this);
            if (link.offset().top < window_bottom){
                link.replaceWith(
                    '<iframe src="' + link.attr('data-embed') + '" class="video" frameborder="0"></iframe>');
                vid_links = vid_links.slice(1);
            }
        });
    }
    showVideos();
    $(window).scroll(showVideos);
});