Impromptu Headshots

What do you do when you were hired to do pretty generic coverage of a short daytime event and they ask you to throw in some headshots for their website?  After hiding the fact that you don't have the ideal equipment on hand, you discuss usage and payment, and then find the cleanest solid background available near a window.   I won't win an award for technical perfection, but for a single light source and one minute of notice, everybody ended up happy.