Gabion walls of recycled terracotta pots is featured in The Real Rubbish Garden by Claire Whitehouse, an environmentally friendly garden with recycled household materials, at The Chelsea Flower Show 2005 in London.
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.