Game 1: Pass the Firecracker
A leader is picked and everyone gets in a circle. The leader pantomimes the size of the firecracker and the others in the group have to copy it. When it gets back to the leader, the leader will make it bigger or smaller and pass it again. The leader can add sounds and the others must copy the sounds. Then the leader can randomly say boom and the actor with the firecracker has to react (they can be scared, excited, shocked, etc.). Another variation is to let each actor change the firecracker size and sound. They have to copy the size and sound given to them but then they change it when they pass it to another actor.
Game 2: Where does the 4th of July come from?
A leader pretends to be a narrator of a documentary and the actors must act out the documentary the leader describes. They can do it as a slideshow/powerpoint with still picture poses or actually act out what is being narrated.
Back in time to early America...
Game 3: Inventions with Ben Franklin (aka props)
All the actors are Ben Franklin. Give the Ben Franklins weird things and he has to say what they do. The object can do another except what it really does.
Game 4: Questions Only while Writing the Constitution
Actors get in two lines are represent the Founding Father writing the Constitution. They argue and make suggestions for the Constitution but must do it in the form of a question. If they make a statement or don't use a question, then they must go to the back of the line.
Game 5: Here Comes Madison
"James Madison was highly unpleasant. Bill of Rights champion and Jefferson protégé James Madison, was called “a cloistered pedant”, “cold and repulsive”, “a gloomy stiff creature” and “the most unsociable creature in existence” by contemporaries. He was also a hypochondriac who never traveled because he feared the effects a cold Atlantic Ocean would have on his health." But he wasn't all bad. "James Madison tried to found a National Brewery and a position that we feel would rival head of the State Department in prominence: The Secretary of Beer."
Now for the game. Actors will play early American colonists who are at a brewery that James Madison is trying to start. Before he comes out to take their order and serve them, the actors give him one strange attribute that Madison must act out. Then Madison leaves and the colonists give him a new trait/problem. Madison returns with both the old attribute and new problem. This can be done three times (or more if it is going really well).
Game 6: Pick your General (The Good, the Bad, and the Ugly)
You must pick a General to lead your American troops in the revolution. 3 players (Generals) form a line upstage. The audience provides questions or problems for which they need advice, and the 3 Generals provide good, bad, and really bad advice. Good advice should be good, bad should be opposite of the good and ugly should be an even worse version of bad. Once one set of good, bad and ugly advice is given. Other actors (soldiers) can act out the advice if you want to extend the game.
Game 7: Stand Sit Slump
3 colonial army scouts are looking for British soldiers. One must be standing, one must be sitting and one must slump down on the ground. After each actor says one thing, the last actor to speak must pick a new position (stand) and the others must adjust and pick the two remaining positions (sit and slump). This can continue until a high moment of humor or until one actor messes up.
Game 8: Lines from our Pocket The audience writes funny lines on pieces of paper that the actors can not see. The actors put the lines in their pockets. The scene is about Paul Revere looking for a good catch phrase to call out to warm everyone about British soldiers coming. Each time the actors want to suggest a phrase to Paul, they take one of the funny lines from their pocket and read it.
Game 9: The Revolution in a Minute Two people get a suggestion from the audience about a famous moment in the American Revolution and perform a scene which is timed and completed in 60 seconds. The same scene is performed in 30 seconds and then again in 10 seconds.
Game 10: Toy Soldiers 1-2 actors are colonial soldiers and 1-2 actors are British soldiers. They must do battle but none of them can move on their own. They can only speak. 2 audience members must move them in to battle.
Game 11: Revolution Victory Party
One actor is the host of a victory party. He has invited both real and fictional American Revolution figures (Betsy Ross, Molly Pitcher, George Washington, Paul Revere, etc.). Audience members can write down names of famous Revolutionary people and then other actors are given those papers. The actors come to the part as those characters but can't reveal their name). The host must guess who the actors are.
See more improv ideas at http://freedrama.net/improv.html