Mithraism expanded rapidly throughout the Roman Empire (and possibly the neighboring Persian Empire too) in the second century. It was stopped through persecution and widespread massacres by Christians in the early 4th century. Since we now live in the new "Roman Empire" it is time to get things right and ressurect Mithraism.
Which I believe people are already doing through Pagan Art events such as Burning Man. We just need to give them a substance to fill the form already evident.