Pew Research is my favorite polling resource, partly because they ask such interesting questions, and partly because they are so transparent about sharing their methodology. (For examples, see their Methods page or click on the full Report Materials for a study they did on gun ownership in America.) They make their sampling techniques and question wording easily available.
Now Pew has shared a video that explains how a sample of 1,000 can be used to draw inferences about the population. Instructors: Save this one for when you teach Chapter 7!