One of the interesting themes I like seeing in wargames (and in particularly games with the crazy bunch of people from Wargames Developments) is when the concept of a game is pitched back to its most basic form - but still plays well. The basis of a few rules that devolve "great simplicity" or as John Gribbins would say Deep Simplicity (see below, a book on chaos that I liked reading):
One such game
Quadwrangles was a mobster themed gang war in old Chicago Town (see below, the godfathers of the mafia muster their forces in a showdown):
Random resource placement, variable [mob] weapon values and a chaotic sequence of play makes it interesting (see below, blood on the streets and one family finally dominates):
Stripped back without teh chrome to its basic form (see below, more network math than mob):
It plays well with friends. This themes and many other themes are bundled together and available at:
Note: Note I am not the author or on commission ;)