Birth of America is a big, sprawling wargame of the American Revolution and the French and Indian Wars, with a map covering the whole eastern portion of the North American continent (including Quebec, and up to the Mississippi). Though strategic in its approach, you play at an operational level, ordering individual regiments on a detailed map of the area. Although it's turn-based, enemy units move and fight at the same time as yours, so unlike many turn-based games, there's a real sense of the fluidity of combat. (Or to put it another way, it's not an "I go, you go" game--rather, both you and the AI plan your moves, and then you watch as the results of those plans play out.)
Demo contains the tutorial and the full 1775 campaign--quite a lot of gameplay at no cost.
Designed by Philippe Thibaut, who was one of the co-designers of the superb game Europa Universalis, Birth of America has something of the feeling of games like Heart of Iron (without the somewhat rococo complexity of that game--18th century warfare is a simpler beast, after all). Mind you, this is not a simple game--as an example, each unit can be put into one of four 'postures', ranging from "attack" to "passive"--and reading the manual is not a bad idea; but it does contain a decent tutorial, the UI is fairly intuitive, and it is far easier to come to grips with than most wargames.
The Revolutionary War is not a subject that has received much attention in the game industry (and the French and Indian Wars even less so); it's nice to see so robust and detailed a treatment.