These are some technical papers I have recently found on the web, on the topics that interest me professionally:
Brian Karrer, M. E. J. Newman: "Stochastic blockmodels and community structure in networks" (seen at the Lens 2011 conference).
Tim Roughgarden: "Algorithmic Game Theory primer" (a short intro to his book).
Hugo Mercier: "Why do humans reason? Arguments for an argumentative theory" (makes the point that reasoning evolved to win arguments, not to search for the truth).
Johannes Neidhart, Joachim Krug: "Adaptive walks & extreme value theory" (I think this has implication for the evolution of various markets, including the Internet).
Denys Pommeret, Mohamed Boutahar, Badih Ghattas: "Nonparametric test for detecting change in distribution with panel data".
Constantin Rothkopf, Christos Dimitrakakis: "Preference elicitation and inverse reinforcement learning".
I also found the preprints of a book that was lauded at the Lens 2011 conference (no, it's not an illegal torrent, it's a preprint put online by one of the authors):
Marc Mézard, Andrea Montanari: Information, Physics, and Computation (Oxford Graduate Texts): Hardcover @ Amazon; preprint PDF.