Though you can find interesting hanging containers at craft stores, here's one that's easy to make yourself.
Create a cone from wire mesh. Ours is copper but almost any metal screening might work. Use wire to "sew" the seam closed on the back and to create a hanging loop at the top.
Fill the bottom of the cone with miniature pinecones, then set a clear plastic container in at the top. (We used a 1-quart plastic deli container.) The container should sit about an inch below the top of the cone.
Fill the container with wet floral foam to help keep the arrangement fresh longer. Disguise the container and foam with more mini pinecones inserted between the container and the mesh cone.
Finally, create an arrangement with a variety of grasses and greens. Ours includes dusty miller, eucalyptus pods, draping amaranthus, miniature pinecones, and wheat-like green grasses.
Hang on the door and secure the pointed end of the cone using removable adhesive putty to keep the arrangement upright.
TIP: For a longer-lasting arrangement, simply create it using dried or artificial leaves and berries.