?!

This was actually shown to me a few weeks ago, and I had intended to write about it then, but I didn't, and it got passed over for a while.

Occasionally a sentence can be both a question and an exclamation at the same time. To signify this, these sentences are usually ended with both a question mark and an exclamation point. Apparently, though, a punctuation mark was invented to merge them together, called the Interrobang.

‽

That probably won't show up unless you're using Unicode fonts in your browser, because its not a standard ASCII character. In any case, its a rather handy symbol, and a shame it doesn't get more use.