It seems as if also my blog cannot be spared form plugin issues.In this case it was the newest
release of FancyBox for WordPress which is, in my opinion, a cool plugin to pep up the blog
especially when using lots of images in a post or page. So what did I do to get the newest
version to work properly. The author posted a tweet asking everyone to default the settings,

if they experience any problems with the plugin after updating. So I screenshot all my settings and reset them to defaul, having the possibility to reconfigure the settings and hopefully get a working FancyBox for my Blog again. Guess what, the trick did it well

So hopefully this message will help you getting your FancyBox working as well!

Oh and thanks to the author for this great plugin!