My all-time favorite graphic to draw is a portrait. In my opinion, it humanizes the chart. I draw portraits of people and its different hairstyles as a way to bring a little bit of humor and even foster interaction, as people often try to find themselves or colleagues in the portraits. Very often I draw them faceless so I leave room to the imagination of the participants.
It's interesting because many times I'm drawing live with my back to participants and when I finish I always got a few hairstyles right of people in the room.