Ancestry.com finally sucked me in, last week. My brother's done a lot of research on my family, but we really didn't know much about my husband's. I took what little I knew, and now I'm back to the late 18th century, when his German ancestors arrived. There's a lot more available information on the German side of the family than the Irish.
One of his maternal ancestors died as a POW at Andersonville. Another fought in the War of 1812. His maternal grandparents families basically lived next door to each other for about 100 years. I think my DH is related to himself, at this point!
Several different branches of the extended family have done research that I've been able to poach. I've also found photos of several relatives he never knew about, some of whom he bears quite a resemblance to.
Of course, I didn't get much sleep this weekend . . .