There's a whole slideshow of possibilities, on my home page.
Or you can find some great local thing to participate in. If you're anywhere near the Wasatch Front, two great options are the Orem FreedomFest, and the week-long Patriot Camps for 1st-6th graders.
FreedomFest has several free events, including the Walk of Freedom, "Cries of Freedom, the Musical", and Constitution Hall.
If you'd like something low-key that keeps you inside with the air conditioning running, watch The Swamp Fox, a Disney series on a real-life Revolutionary War hero. Keep in mind some things are embellished in it; for instance, Francis Marion (the Swamp Fox himself) was actually only 5'2" and 42 years old. But it's good family watching and can lead to even better reading up later.