I always think very basic patchwork done in homespuns are boy friendly like a Log cabins, D9P, warm wishes or just simple squares and rectangles sewn together. I like to go to thrift stores for mens shirts for homespun fabric, can't get much more inexpensive then that!
Designs like Buckeye Beauty or Jacobs Ladder look great done in all blues or browns and tans also make me think of boys quilt. For the younger set of boys, I bet there are panels in whatever is popular for boys at the time, like the movie Cars, Transformers, Yu-Gi-Oh (or however it is spelled), comic book super heroes or perhaps something based on a popular video game. Then you can add patchwork borders ala round robin style to build it out to quilt size. You need to find members in your group with male relatives that age and ask for their input.