Lizard People => Politicians are emotional beings and use the primitive reptilian regions of their brains to make decisions
Intelligent Design => We humans could design life and shape the surface structures on another planet
Pioneering Hoaxers => With the invention of modern day computer graphics, digital film/videos, and multimedia software it is entirely possible to artificially similute the appearence of being the first to encounter the surface of an unexplored location without ever going there. (Video games are dreamed up interactive versions of this, and open source games such as Second Life allows the general public to openly participate in "creating new worlds"....particularly imaginative people could simulate being in parallel universes, even) However, a hypothetical new world always gets disproved when more data is obtained about the nature of a new world, unless the hypothetical exactly matches the objective, in which case the hypothetical really is what it claims to have been. People who claim that NASA faked the footage of the lunar landings or the mars rovers footage fall into the category of "Pioneering Hoaxer Conspirators".
Climate Change => It is entirely possible to change the climate on Earth or terriform other planets to suit our needs (Antarctica Sea Ice -is indeed- growing at a faster pace than the Arctic Sea Ice is declining....perhaps due to the artificial van allen belts created during project the high altitude atomic tests of Project Argus in that region blocking sunlight over the years)
Hybrids => This can indeed be done by humans with life on another planet or even with other life on Earth....all kinds of genetic experiments are possible, some of them could enhance our own genes giving us superhuman strength or perhaps the reflexes of a cat.
Telepathy => Are we on the verge of implanting microchips into the vocal, audio, visual, taste, and smell nerves of people that are attacheable to radio wave antennas which can communicate thoughts and feelings between people? Perhaps that might be the future of communications.
Antigravity and Flying Saucers => Perhaps the supercollider research will reveal the existance of "antimass" with the disintegration of micro-black holes .... with gravitation, likes attract and opposites repell (that runs contrary to electromagnetism which likes repell and opposites attract), perhaps that explains some of the phenomina related to the mysteries of dark mass and dark energy, and black hole jets of (anti)mass.
Time Travel => Perhaps negative mu (magnetic permeability) materials cause light, and therefore information, to travel faster than the speed of light in a vacuum. The effect on the observer is that time goes in reverse, that the doppler shift is inverted.
...etc, a lot of neat ideas come from studying the conspiracies, it's really all about taking off our Black thinking caps and putting on our Green and Blue thinking caps.