Make a backyard bowling alley. Add food coloring to clear plastic bottles of water. Use party streamers as lane margins. Add glow sticks for night bowling. (These would make great outdoor table nightlights also with the glowsticks, gonna try it!
Tea set bird feeders You will need: Old cups and saucers, matching or not A pencil Cloth-backed coarse grade sandpaper An all-purpose glue or hot glue gun Fishing line, or hanging hooks for bird feeders, available from specialty stores (Diy Garden Party)
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.