Okay, this one is a little specific, but if you happen to need a gift for a science geek who's expecting or recently had a kid, I highly recommend Experimenting With Babies by Shaun Gallagher. The book provides all sorts of examples of activities you can do to test things like the Babinsky reflex, which basically involves tickling the sole of the foot and watching whether the toes curl up or down. The answer might give you some insight into how long it can take for your baby's nervous system to develop and reach certain milestones. Overall, the book provides a fun way to discover some interesting and surprisingly useful things about babies that scientific research has uncovered. So, like I said, a bit of a niche gift, but definitely worth checking out... if not for Christmas, then perhaps your next baby shower.