The longest minimum-weight path in a complete graph
  We consider the minimum-weight path between any pair of nodes of the n-vertex complete graph in which the weights of the edges are i.i.d. exponentially distributed random variables. We show that the longest of these minimum-weight paths has about \alpha^* \log n$ edges where \alpha^* ~ 3.5911 is the unique solution of the equation $alpha log(alpha) - \alpha =1. This answers a question posed by Janson (1999). 
Louigi Addario-Berry, Nicolas Broutin, Gabor Lugosi