Drumming with Kofi - 1st Sunday of each month at the Unitarian Universalist Congregation of Fairfax in Oakton (http://uucf.org/). The church is located on Hunter Mill Road in Oakton, between Hwy. 123 (Chain Bridge Rd.) and Lawyers Rd.
The complex has several buildings. You need either check the Church's calendar page (http://www.mychurchevents.com/calendar/calendar.aspx?ci=L6K5J4J4H2L6O9L6I3) or the notice board at the end of the parking lot to determine the exact location.
There is a voluntary donation ($1 - $10) for each time you attend.