Civil Disorder is a set of free wargames rules for playing out rioting in city streets. Players represent the security forces, while the umpires and the system game out the mobs.
Maybe too close to home for a lot of people these days …
Rules: Modern
5.56 mm Modern Era Skirmish Rules
5.56 mm is a set of free wargames rules for modern squad-to-squad skirmishes. Players represents squads on one side, while the referee controls the opposition.
Dinky Dau Vietnam Rules
Dinky Dau is a set of free wargames rules for skirmishes games set in Vietnam.
Spectre Modern Operations Rules
Spectre Miniatures offers a set of free wargames rules for modern operations called Spectre. Click on the “rules” tab at the top of the page.
There’s also a line of 28mm miniatures that you can buy, if you don’t already have some. I’ve got moderns in 15mm already.