Well, while I'm not poo-pooing the idea, as I think it would be incredibly arrogant to assume that we're the only lifeforms in the universe; I do find it rather amusing that EVERY time, someone spots 'aliens,' or 'spaceships,' they almost ALWAYS look the same: big metal triangular crafts, and aliens with big heads and huge eyes. And also, the pictures are always fuzzy, distant and ambiguous.
So while I don't disbelieve that there are other lifeforms out there, I am not sure that anyone has ever actually seen anything from another planet - other than space debris.
Views anyone?