I would suggest something simple...remember that you want to have an activity that fits the time limit and also gives you a chance to continue conversation with the PNMs. Some things we've done in the past are: decorating IV bag covers for childrens' hospitals, making bookmarks for the elementary schools, and creating felt-hand puppets also for the childrens' hospital.
Since you're also an AGD, you might like this philanthropy idea called "Lick Diabetes." You buy cheap little planter pots (the plastic ones are perfect for this), sugar-free lollipops, stickers, and that planter foam stuff. You put the planter foam in the pot (obviously), put the lollipops in the foam, and decorate the pot with the stickers.
Good Luck!