Cooper, Joshua http://cims.nyu.edu/~cooper/
Courant Institute of Mathematics, NYU. Combinatorial problems arising in number theory, algebraic geometry and coding theory. Papers and preprints, talks and resources.
Frieze, Alan http://www.math.cmu.edu/~af1p/
Carnegie Mellon University. Probabilistic combinatorics and its applications in theoretical computer science and operations research.
Propp, James http://www.math.wisc.edu/~propp/
University of Wisconsin at Madison. Combinatorics, game theory, probability theory and dynamical systems. Preprint and teaching material.