I find imaginary play is the way I'm able to breathe new life into DS' interests over time, and it also serves as a gateway to new subjects because you can evolve your play "script" over time. DS3 has been enthusiastic about pets and veterinary care, as well as search and rescue and, today, he, DH, and my parents went on an elaborate search and rescue mission to save his marooned stuffed toys. The expedition included actual aerial rescue maps, a compass, orienteering, building survival shelter, hunting, administering first aid, wearing survival gear, tracking animals, and navigating a jungle climate. So two splinter interests spawned 9 new topics in just one play session. I find the combination of books plus nifty gear--either real or made as a project--generates the most interest. Add museum and site visits as accelerant and you're guaranteed he'll at least want to linger and explore the subject.
