Plickers is an app/website that allows for the use of technology in the classroom but keeps the power in the hands of the teacher. Students are not required to have their own device which can make Plickers useful in classes where not every student has a smart phone or where building policies restrict their use.
With Plickers, teachers can create a huge bank of multiple choice questions and pose them to students via their own device (Smart Phone or Tablet) projected in the classroom. Students then each have a card (printable for free from the website) that can be turned one of four directions that correspond with the A, B, C, D choices. The teacher can then use their Smart Phone or Tablet camera to scan the room, collecting all of the students responses instantly - pretty cool! The results can then be displayed for students or recorded into a grade book program.
Besides just being neat, this tool can be great for getting feedback quickly and adjusting instruction accordingly.