because can be followed by a finite clause:
I left him because [he sold my prize-winning armadillo].
It can be followed by a prepositional phrase:
I left him because [of his unbearable stench].
But a non-standard usage is gaining wider and wider acceptance, namelybecause+noun (often a proper noun):
I can't come out tonight because Skyrim.
This isn't a straight nonstandard equivalent to the other uses - it's different. It means something like 'I'm so busy being totally absorbed by X that I don't need to explain further, and you should know about this because it's a completely valid incredibly important thing to be doing'. This page is all posts that were tagged with #because Skyrim. But has a similar use (taken from the same Tumblr page):
Okay I’d totally love to read my dash and everything but Skyrim.
I like it.
