Update August 2012: thank you all for your answers. I started small as suggested, creating first a Facebook Game about it, the next step will be to port it later on PC for a 3D version, and much later ...
What technical questions do you need to be prepared to answer before presenting an idea to venture capitalists?
A friend and I are planning on pitching an idea to venture capitalists in a few weeks at SIEGE 2010. He is handling the business plan side of things and all those related questions so I only need ...