Building a bird house can be an enjoyable and fulfilling experience. Should youn't really enjoy the notion of making your very own edible birdhouse. And this is good ideas to begin with simple projects.
Elf house on a tree! That would be cute in the garden, especially in the tree over grown with ivy. How about some battery tea lights in the windows during outdoor parties. I hear the fairies/elves whispering "home school project" in my ear.