An adjective. It refers to a particular thing being of the the form, a 'crapsack'. a crapsack is a sack filled with crap. Cracpsackular is used to define the awesomeness of something. Crapsackular, means that that something is really quite shit.
Wow, i just went and saw the movie "confessions of a shopaholic" and let me tell u... It was mighty crapsackular!
That cupboard in your house that is filled with complete shit. The place has no organisation. No one can find anything in there. It's a mysterious place to enter.
Hey Jim, can you run and get me a new light bulb form the mystery cupboard!