I figured someone would mention this, but since no one has, I will. If our dad likes mathematical history in a personal vein, the Math Genealogy Project will create a personalized history of his mathematical predecessors, PhD advisor by PhD advisor, with some branching. And if he's had PhD students of his own, those can be included. One of my colleagues has a framed one on his wall and it's always fun to look at. In many cases, the trail goes back to the 18th century, or even earlier.
