Here's an example of a convenience sample for Research Methods teachers and students. It's a haphazard effort to find out what some people in New York think about feminism. A small amount of people on the street are asked about their views. Only a few men are included, and only a few people over the age of 30 (a safe guess, I think) are involved. Click here for an article that accompanies the video on Cosmo's website if you're interested in how they treated the subject of feminism.