When you eat out, bring your own reusable container to carry home leftovers. You'll save fossil fuel energy and reduce the amount of waste sent to landfills.
Manufacturing the average Styrofoam clamshell container requires about 400 watts of energy-enough to run your refrigerator for about 40 minutes.
If the next time they went out to eat, every family in the U.S. brought their own to-go container instead of taking home a Styrofoam box, more than 5 million pounds of waste would be saved from landfills. The effect would be equivalent to 1,700 households not generating any garbage for an entire year.
Sources:
American Chemistry Council (PDF)
U.S. Census Bureau