Ok, so who exactly is Simon and why should we do what he says? I asked this question to Cecil and never got an answer (for reasons unknown), but I would really like to know what the origin of this crazy game came from.
While I can’t answer your question as to “who Simon is”, I can tell you that the phrase “Simon says” can be traced back to at least 1870, thanks to Barry Popik.
There is a reference to a game called “Simon” in 1853(Mathews), but no more info than that.