Googler Joshua Bloch reports that "Nearly All Binary Searches and Mergesorts are Broken" due to an integer overflow bug. Awesomely geeky.
By the way, "Programming Pearls" really is a great book. It's full of fun little algorithm problems. Some might consider it old school due to the focus on C and low-level performance optimizations, but, hey, when optimization is important, it is important.