We had den flags that the dens made several years ago, and were reused year after year.  When I took over this summer, I picked up cloth in orange, yellow, light blue, and forest green for the dens.  We printed the Den logos on iron-on paper and put them on the middle of the flags.  In the first two meetings after roundup, the dens decorated the flags however the boys decided. I thought this would be a good way to get the dens to start working together a little faster.  So far, it seems to have worked for them.  They all had a good time brainstorming their designs and working on their flags.