Ok. This is neat. It’s a Java window that shows how fast one infected individual can destroy a population.
Zombie Infection Simulation v2.3
modern
FireForce!
FireForce! is a set of free wargames rules for 15mm platoon level modern skirmishes.
De Bellis Vietnam
De Bellis Vietnam is a set of DBA-based quick and dirty rules for wargaming Vietnam.
Chechen Conflict Rules
Here’s a one-page set of free wargames rules for the Chechen Conflict, with figures based on on stands.
Indo-Pakistani Campaign for Not Quite Mechanized
Chris Kemp has a mini campaign for his Not Quite Mechanized rules.