Emil Johansson is attempting to build a Family Tree that holds all of the characters in Middle Earth. As of today, there are 646 entries.
The family trees of American politicians - There are those with very long blue blood pedigrees, and there are those with very short and unknown pedigrees. There are also some surprises, like a certain Democratic senator and possible '08 Veep pick being somewhat closely related to the current Veep, or that certain ex-mayors have family trees that were apparently a bit inbred back in the old country. Other fun tidbits: Newt Gingrich's father was illegitimate, John Kerry is related to the rabbi who created the Golem of Prague, Pat Buchanan is related to both FDR and Marilyn Manson, Wesley Clark's father was a Kohan, Martin Luther King was born Michael Louis King, and Gary Hart was born Gary Hartpence, which was in turn derived from an ancestor named James Eberhart Pence. (more non-politicians here)