Go to the library and browse through the current and back issues of The Communications of the ACM, which is a high-quality, broadly accessible, general monthly. (If you are a student member of the ACM, you'll have your own copies; if you aren't a member, ask me about membership.) You should also look at ACM Computing Surveys, a quarterly containing longer ``survey'' articles that summarize the state of the art in a particular area, and IBM Systems Journal, a research journal with a real-world slant. (Of course, there are many other publications as well, but our library gets these three, and they are among the more suitable for this assignment.)
Choose one article that interests you, and which is challenging technically but not entirely unintelligible.
Write a one-page critical summary of the article. Be sure to include complete bibliographical information. A critical summary should briefly summarize the article's main points, and should also contain some information on your reaction to the article.