I get this question sometimes, so I thought I would share..
Two Moms and I started a small classical/Charlotte-Mason cooperative 3 years ago, really 4 if you factor in the prior planning.  We spend hours designing what the schedule of classes will look like, who teaches what, where each child goes, etc.  The children wear uniforms.  We probably look like a private school in some ways.  There is a small fee to join, and the moms or Dads help teach the classes. We meet once a week for the months of September through the following April.
Here’s an example of what our fourth-sixth grade class is learning for the fall semester:

Assembly-prayer/pledge/Bible recitation of Psalm 100

Memory work: the Gettysburg Address, states/capitals, history timeline cards from VP

Visual Latin

History-Story of the World IV, biographies

Science-chemistry (scientific method, atoms, molecules, famous scientists, polymers, mixtures, acids/bases, reactions, chromotography, periodic table, etc)

Art History-Picasso

Music History-Gershwin

Language Arts-“My Side of the Mountain” book with an emphasis on various writing elements, 5-paragraph essay

Our younger age classes look similar minus the Latin, and the history books are “Story of the USA”.  They sing geography songs and are memorizing poetry by Stevenson.  Literature consists of either “Mr. Popper’s Penguins” or the “Beatrix Potter tales”.

I use the co-op to fill in gaps that I see in our home studies.  The kids enjoy spending time with friends, but that’s not my motive for participating.  It’s (I hope) academically rigorous.  We keep slightly changing the curricula every year to up our own standards and to adjust to the needs of the families attending. Lots of benefits to doing so-downside, it’s a lot of work! 🙂