I was inspired by Renee Smith's post on 10 ways to use Instagram in the Classroom. Great ideas. As I continued the search on the web for more ideas I ran across a more recent post with many of the same ideas, but a few new ones.
http://blog.leeandlow.com/2015/03/09/10-ways-to-use-instagram-in-the-classroomI like the idea of...
Caption That! For a variation of the writing prompt, post an interesting photo and ask your students to write a descriptive caption in the comments. Differentiate how challenging this task is by asking students to write their caption using specific sentence types, different parts of speech, clauses, prepositional phrases, and their current vocabulary words.