Social media is taking over our students' lives, so why not try to incorporate it into the classroom? I made a series of signs using the icons from the reactions on Facebook. A banner to go above the signs is provided. My thinking was, if laminated, you could periodically poll the class (perhaps using a Google Form if your school uses Google Apps) to determine how students "react" to a certain lesson, then use a wet-erase marker to keep a running tally. Example: 5 Likes, 2 Loves, 7 Angry, etc.
Inside this .zip file are Microsoft Publisher files for each sign, you may customize how you like. If you don't have MS Publisher (it is included in most versions of Office), I included the icon files as well. Icons taken from Google Images.