I never got around to posting my Numb3rs review because this episode was rather low on the math. There was a small element of Bayesian reasoning, where Charlie attempts to figure out the likelihood that Charlie convicted the wrong guy based on two crimes having the same M.O.
Plot Summary: Don discovers a crime with an M.O identical to a case that he thought he had solved a year ago. He gets Charlie to tell him that the likelihood of a coincidence was very small, and then goes after the real killer. Along the way, Charlie insults a fingerprint specialist, but she gets her revenge, with a "butcher's hook" (no no, not that kind).
What I found more interesting was a real life Numb3rs story (with no crime though), via the New Yorker, starring the brothers Chudnovsky, and a delicately tampered rug. And if you're tired of such seriousness, check out this profile of the most beautiful mathematics grad student on TV, Navi Rawat (courtesy Sepia Mutiny).
Tags: Numb3rs, review