I recently photographed portraits of participants in Adobe's Creative Jam in Washington, DC. The group consisted of designers, photographers and other creatives, and I wanted to make the portraits a little edgier than I normally would.
These portrait were for each individual person, and don't need to match each other. I created a lighting setup that would allow everyone to do something a little different, and we could try different poses for each person. I set up a small softbox overhead for the main light and a large umbrella directly behind the camera for fill. This set up let the subjects move around a good deal without impacting the light.