Simply put... this has been about the best site I've seen this week! And certainly the most fun!
You have got to visit ALIEN SPACESHIP THEORY OF GENEALOGY to read one family's take on where their family came from, and why there are no documents available to prove or disprove their existence where they were known to have cohabited!
I have absolutely fallen in love with this theory, and believe I may actually have one or two ancestors who arrived, and thus disappeared, in like manner!
Be sure to check it out!