Apparently this thread got deleted, so I'm going to rewrite it.
You have two or more teams, each with a flagstand, a flag, and a fort. There is another fort in the middle which contains more powerful weapons and its own flag and flagstand. The object of the game is to get the flag in the middle and the other team's. The flag in the middle looks different from the flags in the teams forts.
I did this setup with a red team vs. a blue team, with the middle fort being yellow. The neutral flag was yellow, and the team's flags were identical, being checkered victory flags.

