C: Computer

To your students, it's a fun toy that they've grown up with, and they have no idea how to use it, apart from posting incriminating pictures of themselves on the internet and telling the world about every little thing they've ever done. Don't bother talking to them about email attachments or timestamps. In fact, don't even bother talking to them about email--that's so last decade, man.

Sample sentence: Yo, student, turn off that damn computer and pick up a freakin' book.