This Christmas project of building a Healthy Gingerbread House is a real winner with my 5th graders. I use it to promote good nutrition, and and it takes the place of a junk food party. Although students build their own houses, they work in cooperative groups sharing their resources. This project can be done on any grade level. I usually have students help bring the ingredients. There favorite seems to be shelled pistachios (Costco and Wal-mart carries these).
Tip: Check out your local dollar store. Mine carries the banana chips, peas, and sturdy plates.