Here’s a great activity for beginning and more advanced classes alike: the 7-Word Autobiography.
Brain Pickings describes the origins of the 7-word autobiography as part of the New York Public Library Live interview series, and gives some wonderful examples of the autobiographies of famous figures who’ve taken part in the series.
As for a classroom activity, it would be as simple as it sounds. It would make a great first-day activity; first I’d give some examples and then let students write their own. They could move on after that to writing them for famous figures or fictional characters. At the end of the session, they could even write them about each other!
Beginners’ autobiographies might just be a list of 7 words, while I’d challenge more advanced students to be a bit more playful and creative either with the prose form, or by stretching the limits of their vocabulary.