Good to hear from you again!
I've been looking into your Calendar page, and I believe the reason Fancybox isn't loading is due to the dynamic "More Info" dropdown the images are contained in. At a guess, it seems you've either got your NextGEN shortcode nested within another plugin's shortcode for the effect, or it's being inserted via a direct do_shortcode() call.
Unfortunately, it's not currently possible in WordPress to detect if either of these methods are used on a page before the head section is loaded (re: Optimizer's FAQ), and loading the extra lightbox scripts sitewide would defeat the purpose of the plugin.
However, I've recently come up with a solution whereby if you tell Optimizer where you want the necessary scripts to run, it will both load them conditionally in the head where they won't break, and only on the pages you specify (not sitewide). I'm currently working on a conditional-building form for the plugin's settings page, but until then, I've just emailed you a custom conditional function that will load the Fancybox lightbox scripts and styles on your Calendar page only (in addition to your pages with regular shortcodes).
Hope this helps!