Coming way back from ancient Greece is another "fringe" period that is actually better known to everyone than, lets say, the Spanish American War. This is the Texas Revolution or the Texas War for Independence.
I didn't find too much on this time period, other than some battles, like the Battle of San Jacinto, and the Battle of Coleto Creek. I think this is a cross-over period, with few groups dedicated to the Texas Revolution, but the bulk coming from reenactors from the Mexican and Civil War periods. The largest group is the Texas Army, which seems to be the major umbrella group to this time period.
The Red Rovers from Alabama are an exception to this. This group is one after my own heart. They are a little known piece of history outside of Alabama, and portrayed by reenactors who want to make sure this little-known slice of Texas Revolution history is represented correctly.
The Texas Revolution also has its own forum, The Alamo, which is also a repository for many things reenacting and Texas.