My mom used to make "Silver Bell" door decorations from plastic cups. 1)Wrap the cups in aluminum foil; Punch a SMALL hole in the bottom of each cup. 2)Measure 3 pieces of ribbon or yarn - 2 the same length and 1 slightly longer; tie a jingle bell on one end - tie a knot in the ribbon about 1" above the bell. 3)Pull the end of the string without the bell through the hole in the bottom of the cup, leaving the jingle bell to hang inside the cup ( the cups will be hung upside down). 4)Arrange the 3 "bells" so that the bell with the longest string is in the middle and 2 shorter on each side; tie the 3 strings together at the top, making a loop to be used as a hanger. 5)Cover the tied end with a Christmas bow, picks, etc... - whatever you would like and hang on your door.
I hope I made this clear; you can pretty much figure it out as you go but if you have any questions, I'll try to answer. These are nice for the kids to make and give to parents/grandparents/neighbors, etc...
Also, if you use colored cups, you wouldn't have to cover with foil if you didn't want to.