Double Agent

Double Agent is very simple to set up and play. The game is best played with between 20 and 40 players, and can be played with or with out a time limit. Respawns should be kept to a maximum of one per person.
To start, each of the two teams pick bb's out of a hat at separate times. All are the same color except for one (two in the event that there are more than 30 players), and the person who picks the other colored bb is designated as double agent. Nobody on either team is allowed to tell anyone else wether they are the double agent or not, nor show anyone else what colored bb they picked.
The game starts out as a normal TDM, but after a time limit (typically 7-15 minutes, depending on amount of players) a whistle is blown, signaling that the double agent on each team can reveal him/ herself (but does not have to). The double agents are now allowed to fire on anyone, including previous teammates, and as such become fair game for both teams AND the agent on the opposing team. Alternatively, the agent can keep their status a secret and continue to play alongside a current teammate.
This game is about deception. Even before the whistle blows, assume everyone else on your team is the double agent and be weary of suspicious actions or anything out of the ordinary with a teammate.