Database of Mathematical Models
A variety of mathematical models and sources of information about mathematical modeling are available here.

Modeling and Simulation of Ethnic and Social Processes
A site at Omsk State University in Russia.

Three sites with information that could be useful in developing a model to help decide whether to buy or lease a car.
Site One Site Two Site Three

Two sites with information the could be useful in developing a model to test voting methods.
Site One Site Two

Three sites with information that could be useful in developing game-theoretic
models for the War of Spanish Succession.
Site One Site Two Site Three