I consider the possibility of a lot of things without committing to any strong bias about the truth. Here's some ...
  1. Alpha Centaurians
    There's an intelligent bipedal race inhabiting a planet in the Alpha Centauri system. They're civilization is far older than ours, and far more gentrified to their own detriment. An algae bloom gives the oceans a magenta hue.
  2. Secret Space Fleet
    Remember the billions the US spent on stealth fighters and bombers? Where are they now? Defending our solar system from interstellar threats, that's where!
  3. Mars Colony
    People have been living on Mars for decades. The atmosphere is equivalent to 14k on Earth and the monsoon season supports desert grasses. It's mostly McMansions and not that impressive.
  4. Teleportation
    There are chambers in a room beneath Cheyenne Mountain in Colorado Springs that can teleport you across space instantaneously, but it takes a lot of power and is really uncomfortable. Nothing as elegant as Stargate.
  5. Dagobah
    The left star in Orion's belt supports a misty green planet heavy with life, though I could make no intelligent contact.
  6. Multiverse LHC
    The Large Hadron Collider exists in many pages of our universal book, and may be part of a much larger plan to return us all to the singularity.
  7. Grays
    Those bug eyed aliens we know so well from pop culture are a genetically engineered hybrid created to enforce the political whims of a larger galactic governance.
  8. ECCO
    The work of J.C.Lilly suggested ephemeral beings which guard our boundaries of consciousness. Just treat them like any other authority figure and avoid them. They could send you to brain jail.
  9. Subterranean Reptilians
    They sheltered some humans through the last ice age in underground caverns all over the world. Good and Evil don't apply to them, their brains only recognize survival. They kept us alive as a food source through the long winter.
  10. Tiny T-Rex
    A Navajo told me he saw one in a canyon on the Rez. Having seen the canyons there, I wouldn't be surprised.
  11. Samsquanch
    Bigfoot, Yeti, Grassman, Skunk Ape. Whatever you want to call them, I met one. He had four dogs and he gave me one. True story.