What connects quiz-show winners, on-line poker cheaters and cyber attacks on Taiwanese national ID cards? In this talk I’ll present a historical overview of randomness failures. Why are random number generators so often at the root of cyber-security problems and why are they so damn difficult to implement in hardware? I will go over several incidents of security failures caused by bad randomness in the last few decades, and from each incident we will try to learn what not to do. Finally, after eliminating all the wrong ways of generating randomness, possibly we’ll be left with the correct one.