The recent uproar over Virgin Mobile's less-than-adequate password security came at a particularly good time for me, as I was teaching about permutations in my Advanced Functions and Modeling class. I definitely recommend that you read the details of Kevin Burke's discovery of Virgin's massive security hole(s), but the short version is that he discovered that it was ridiculously easy for someone, even someone who wasn't a major tech-savvy blackhat, to hack into a Virgin Mobile online account.
Just before this story hit the internet, a student in my AFM class was asking me about real-world situations that would involve calculating permutations and combinations, and I actually mentioned data and password security in my response. I happened to see the story online the next day and I printed it off and passed it out to my class, mentioning that I happen to have a Virgin Mobile phone, and that if any of them were able to hack into my account I hoped they would let me know since they could probably pick up some extra credit for it.
But within a couple of days Virgin had closed the most gaping of the security holes, so I suppose my account is safe for now. (Though they still haven't addressed the problems with their call history data.)