All:  Last evening I did the Potomac River Running's Women's Only Group Run & Walk that starts from the Arlington Potomac River Running Store at 6:30 on Thursday.  The group naturally broke off off into different paced groups so no one was "held up" or forced to run too fast.  Apparently they do several different loops through Arlington (well lit, but you can bring a head lamp or small flashlight if you prefer), with a bailout option back to the store midway through the run if you want to do a shorter distance.  Last evening we did a 4.4 mile run, and the bail out was at 2.5 miles.  
 
I will be doing these runs most (though not every) weeks and will bring Luna snacks when I can.  Hope to see some of you there!
 
For more details:
 
http://www.potomacriverrunning.com/details.asp?p=training_group_fun_runs