At the end of our first seminar class Catherine mentioned an Orienteering event this coming weekend.
Here is the link to the hosting club, New England Orienteering Club (http://www.newenglandorienteering.org/). The event itself is listed on the schedule (http://www.newenglandorienteering.org/sched.htm) - it's at Great Brook Farm in Carlisle, MA with start times between 10 am and 1 pm. And there will be lots of beginner instruction!
Catherine has secured a carpool with someone from Cambridge's local orienteering club for up to 3 newbies. We will be leaving from 77 Mass Ave (actually, the other side of the street) at 10 am on Sunday, and probably back by noon or 1. Contact catherio@mit.edu for more information.
Bring good shoes for walking/running in.
NOTE: Great Brook Farm is about 5 miles north of the area that we plan to map.