

Well this seems very suspicious, I would think it's a prank with fake money.. I don't think I would actually believe it's real
I would call the cops, I mean what if it's some kind of illegal money deposited by some criminal organization to hide it or to misguide the feds or something, I mean I don't think anyone with such amount of money does a mistake like "delivering to the wrong address"
Push that cube to the basement, sleep on it for a couple of days just to see what happens. If no one calls or comes to the house the I mean I basically can start spending. I think I would start by moving out of the state or even the country.