BrikWars

From the site: BrikWars is the plastic-brick wargaming system that throws the peaceful worlds of your favorite construction toys into wanton chaos and destruction!

BrikWars is a miniatures wargame, but unlike more serious wargames, BrikWars is intended for battles between toys, and especially plastic building bricks and other construction toys. The BrikWars rules let players take turns moving toy troops and toy vehicles through toy terrain to attack one another with toy weapons and die horrifying toy deaths.