A lot. Here is partial list
Cellular automata and discrete systems: dynamics and attractors, synchronization and control, phase transitions, entropy and chaos.
Evolutionary patterns and biological modeling: Speciation, competition, small world effects in evolution, risk perception and epidemics, data mining, networks.
Brain, cognitive sciences, psychology and social dynamics: opinion formation, group dynamics, evolving neural network structures, data mining, community dynamics, archaeogrid, networks. See also the virtual laboratory of human behavior.
Environmental modeling: Sand transportation erosion, landslide, earthquakes.
Physical modeling and experiments: entropy and chaos, synchronization and control, Lattice Boltzmann Equation, plasma physics, chemical reactions.
Computers and education: Distance teaching, wikis, programming and interfaces.