Take a cue from professional innkeepers and invite your guests to record their names and memories in a guest book. Next visit, you can all look back on your time together.
Start with an 8 ½ x 11-inch hardbound sketchbook with acid-free paper to help preserve photos. (Art supply and craft stores offer a variety of sketch- and scrapbooks that would work as well.)
Keep a cup of colored markers nearby, and include mementos such as children's drawings, pressed flowers, and ticket stubs.
For mounting, consider using a restickable glue stick, which allows you to reposition items without destroying the pages.
Leave plenty of space to add photos later.