One of the members of our Meetup Group was directing a play (Othello) and was able to provide access to our group members to the final dress rehearsal.  This was a really fun shoot, but technically it was very challenging.  The only lighting was the stage lighting, and we had to stay out of the way of both the actors, and each other.  There were about 5 or 6 photographers ringed around the edge of the stage, all shooting.  The low light meant using really fast lenses (I used my Sigma 30MM f1.4 and my Olympus Zuiko 14-54 f2.8-3.5 zoom lenses), high ISO, and slow shutter speeds.  The latter made for some shots with some motion blur, which I liked.  Actors are fun to shoot, they are by nature very dramatic and photogenic, so it made for some really nice shots.