oh rats, i thought this was a thread about the hip hop group Ancient Astronauts
well while i'm here, i'll throw my 2 cents in.
speaking as an anthropologist, i call BS on the lot of it!
there is no good reason to jump to such bizarre and incontrovertible theories when there are completely plausible explanations for these things. moreover, it is irresponsible to try and interpret much of this 'evidence' outside of the framework in which it was produced.
pyramids: this is just old ideas about primitive savages rearing its ugly head. there is no reason to suspect that humans are not capable of building them. i've seen tremendous archaeoastronomical sites in the US that could be used to predict events like eclipses and the motion of the planets with amazing accuracy. not unheard of at all in the ancient world.
as for the technological feat of building the great pyramid - well, with tens of thousands of slaves and many decades in which to work, it's really not that unbelievable to imagine...
gods from the skies: well why not? a tripartite cosmos is a common thread in ancient religion, and the upper world was often one of supernatural beings. no surprises here.
ancient art: if you choose to interpret ancient art from outside of its native sociocultural framework, then you're free to interpret it as you wish - but don't expect anyone to listen to you.
nazca lines: again, why should we imagine humans are not capable of this sort of thing? no need for otherworldy interpretations.
boom in technology: no idea what you're on about here. got any examples?