The key of B# major is extremely complex and quite unnecessary because it sounds like C major. And that by using two sharps and five double sharps. But it exists: in the field of philosophy. The following quotation from the book »Ketzereien« (heresies) of Günther Anders is a nice example of the use of musical terms in communication. Using B# major as a paraphrase for complex speaking is answered with B# minor as a paraphrase for discretion. Here comes the quote:

Soiree after evening lecture of Adorno

When I said to Adorno that he wrote many pages in the key of B# major, he was - as I had hoped - the only one who understood this. And he thanked me that I was so discreet to make my remark in B# minor. The bystanders looked at us as if we were speaking a secret language. And really the stupidity of the others let us exchange a knowing smile.

Quoted after:
Anders, Günther
Ketzereien / Günther Anders. - München : Beck, 1982.

  ISBN 3 406 08570 9

The second occurrence comes from the memoirs of Miklos Rozsa. B# major is used to bring an examinee in a difficult position and to test his talent:

Final exams in Leipzig

In the practical examination, one of the tests was to modulate melodically from one given key to another in only eight bars in front of all the professors, including the head, Sigfrid Karg-Elert, who gave me the near-impossible C major to B sharp major. Luckily I was well prepared and I solved the problem to the jury's satisfaction.