Coffee to Go
This summer when I worked at Art A Fair, come around 2PM my energy level would plummet and I would head over to the the restaurant to grab a coffee to go. Usually the coffee would be poured into the usual Styrofoam cups, when it dawned on me one day to just ask for having it filled into a mug instead. The server was eager to oblige and I was able to reduce the amount of waste on my own behalf. Besides I prefer the taste drinking coffee out of a ceramic mug over that of Styrofoam. 
Image via WikipediaJust consider if everyone where to bring their own mug when getting a coffee to go, we could save thousands of trees and reduce the amount of trash that would have to be dumped into landfills.
Starbucks even sells mugs that look like paper cups, just in case you can't part with the look :)
