Where have you been all my life, the Interrobang? Less so, the Guillemets, despite the awesome name. How many of these did you know already? Be honest.
Now what do I hit in the keyboard so I can use these damn things?
Dagger
Also called an Obelisk. This bad boy (on the left), and its two-headed friend (on the right) the Double Dagger or Diesis, represents a javelin, which is cutting out extraneous stuff from your text. Its primary use through the ages has been to mark out superfluous repetitions in translation, though nowadays it mostly just stands in as a kind of footnote.
Caret
Also called a Wedge, an Up-Arrow, and a Hat, which is cute. The word caret is Latin for "it lacks," which is convenient, because the caret is primarily used to indicate something that's missing from the original text.
Guillemets
Guillemets means "Little Williams," which is interesting but unhelpful. They're named after a 16th Century French printer. Their primary role is in non-English languages that use them as quotation marks.
Because Sign
This one's so cool. It's like the "Therefore" sign, but upside-down, and it means because.
Exclamation Comma
Just because you're excited about something doesn't mean you have to end the sentence.
Interrobang
It's a combo-Exclamation/Question mark, and it's awesome. It is the glorious punctuational equivalent of saying OMGWTF?!