I just saw an interesting tip on how to use up excess yarn by making baskets. Well, I use my excess yarn by making drinking glass sweaters. They are excellent for sweating glasses in the summertime.
To make one, just make a circle the size of the bottom of your glass by increasing stitches each round; then make the side by making the same number of stitches each round until you get the sweater the height you want for the glass.
If you use acrylic yarn, it will be machine washable and dryable and last for years. I usually make several different sizes as I have different sizes of glasses in my cabinet. I especially like to mix colors by making alternate bands.