Chris Kemp has a mini campaign for his Not Quite Mechanized rules.
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Derelict Commercial Building Paper Model
Stoelzel’s Models offers a free paper model of a derelict commercial building.
American Football League Rules
Here’s a set of rules for American style football games.
Vehicular Pursuit Rules For Fistful of Kung Fu
The Osprey Rules A Fistful of Kung Fu 
Ambush Guerrilla Wargaming Rules
Ambush is a set of free wargames rules for guerrilla warfare 1960 – 2000.