Many local amateur, professional or school theatrical productions require large set pieces to suggest outdoor scenes, often built with partial, fake building tops that require real shingles to look realistic. Used and old shingles will often add particular value to this kind of project because many sets will require old-looking housetops. Contact local groups to see if any upcoming productions could use such a donation or if the theater's technical director would be interested in keeping the shingles on hand for a future production.
If dealing with old wooden shingles, these make for excellent fire kindling as they are dry and worn and thus readily combustible. If you have access to a wood chipper, use old shingles to make a kind of garden mulch that has a different color and texture from that made from tree scraps, good for giving your garden streaks of contrasting path colors.
If your old shingles are still in good enough shape to be used on new building projects, try donating them to a charitable organization that deals with home building, repair or renovation. Donations of building supplies of all kinds help these types of groups keep their costs down, helping them to offer more service to local families or organizations in need of building assistance or new homes.
Use asphalt shingles as a means of coating a garden path, making for an even, attractive garden path liner that will keep weeds from growing and provide a pleasant, dark gray contrast to your garden's color scheme. Similarly, keep shingles on hand for when winter snow and ice rolls around; lay down a few to create a temporary nonslip path between doors and driveways or anywhere else they'll be useful in your outdoor area.
Use some of the best-looking old shingles to make small craft projects. The texture and shine of the tiny grains in the asphalt make attractive cutout shapes for decorating small outdoor wood projects like bird houses. Cut out the shapes by using stencils on the smooth backs of the shingles and a craft knife.