If you're lucky enough to have secured some space in the school and an actual file cabinet -- I hope you'll get in the habit of using it well.
But in 2013, this can also be an electronic system, and -- frankly -- an electronic copy of last year's flyer is even more helpful than a printed copy. We outline several excellent, simple resources for this kind of archiving in the article "Getting (and Staying) Organized."
And are you asking your chairpeople to save a post-event report (again: simple -- this doesn't have to be IBM) that you can then save for next year? Here's a great template from our File Exchange to get you started.
Good luck!