What does she like to do?
Is she creative/crafty? She could scrapbook/journal about her summer activities and her friends. Perhaps she could try blogging, with some photo essays of interesting things around her house.
She could start some sewing projects - simple projects like a drawstring bag for the beach, pyjama bottoms, or decorative pillows for her room.
She could try some cooking. Maybe explore some international foods, a different country each week. She could spend a day researching the country and cuisine and find a couple of recipes she'd like to try. Another day could be spent gathering the ingredients (your regular grocery day). Then cook up her feast (with your help, of course).
Building projects are fun too. She could build a bird or bat house or some planters for the garden.