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.
I think there may be some restrictions on which nouns are possible in this construction. For example, while I think it’s fine to say:
I can’t come out tonight because homework/math.
I can’t come out tonight because essays/readings.
I can’t come out tonight because busyness.
I don’t think it works to say:
*I can’t come out tonight because too much/lots of/difficult homework.
*I can’t come out tonight because essay/my essay/an essay/this essay.
*I can’t come out tonight because busy.
So it seems like the because+noun construction really must consist of a bare noun, not a noun with a determiner or an adjective. However, I think I might be able to be okay with:
?I can never get to bed at a reasonable hour because interesting people on the internet!
Also, I think the title “because reasons” may be an even more specialized version of this use, actually. Because you can paraphrase “I can’t come out tonight because Skyrim/homework” as “I can’t come out tonight because OF Skyrim/homework”, but I don’t think “I don’t like him because reasons” paraphrases well as “I don’t like him because OF reasons”.
Update: Where “because noun” probably came from.