Who invented the question mark?

The symbol is generally thought to originate from the Latin quaestio, meaning "question", which was abbreviated to Qo. The uppercase Q was written above the lowercase o, and this mark was transformed into the modern symbol. Another hypothesis about the origin of the question mark proposes that the mark originated in the 9th century, when it appeared as a point followed by the curvy bit written slanted (similar to the tilde, although the tilde was tilted more upward to the right). The point has always indicated the end of a sentence. The curved line represented the intonation pattern of a spoken question, and may be associated with a kind of early musical notation, like neumes.

The question mark come from the latin, the simbol was originated on the 9th century from some one called Nunnios Faria. This gentleman was a sucessful cientist that one day bang his head on the sink and start seeing some signs and this was one of them...I hope you find my explanation helpful. If you requeire any more historical answers, please do ask...

"The question mark first appeared in the eighth century. It was called the punctus interrogativus. Its form took a while to jell, but the general idea was a wavy line slanted up to the right over a dot.

Some have suggested that the question mark and other punctuation are derived from a medieval music notation system called neumes. In his book With Voice and Pen: Coming to Know Medieval Song and How It Was Made (2003), Leo Treitler reviews the evidence and suggests that both neumes and punctuation derived from lesson signs – punctuation had been around before neumes came into common use. He says, "The origin of the lesson signs – which are but punctuation marks in ecclesiastical texts – is the same as the origin of post-eighth century punctuation altogether: invention and normalization by French scribes as an aspect of the reform of language-writing technology."

In the 17th century the squiggly question mark was replaced by printers with the one we know today. According to Lynne Truss in Eats, Shoots & Leaves (2004), there was some question what it ought to look like: "In its traditional orientation, with the curve to the right, it appears to cup an ear towards the preceding prose … But people have always played around with it.""
Source and further information:
http://www.straightdope.com/mailbag/mquestionmark.htm

Further information:
http://en.wikipedia.org/wiki/Question_mark
Early form of the question mark:
http://www.typografie.info/typowiki/index.php?title=Bild:Interrogativus.png

Mark Query he was an inquisitive lad.

I think it was Dr. Evil's father.