This listing is adapted from the work of Grant Wiggins and provides a nice summary of different techniques that can be employed as formative assessments in the classroom. While it does cover non-gesture related ones as well, it does describe the use of hand signals by students. I think this is a good summary that could be really useful to any teacher wanting to create formative assessments.
Penny Strait is an elementary school teacher who is a strong proponent of formative assessment. However, she recommends using an exit ticket approach instead of verbal or gestural techniques. I think this article, while not encouraging of using gestures as a means of formative assessment, is a nice alternative viewpoint.
While not very detailed, this listing gives a great overview of different strategies that can be employed to check for understanding in the classroom. I like how it has several that use gestures, including a "fist to five" response and students holding up different colored cards. This is a nice, simple outline of different techniques.
Here is a very complete listing of many different tools and strategies (paper, verbal, and gesture) that can be used as formative assessment. While similar to other resources, I really like how this listing provides a very nice description of the technique. I think this would be a great place to start.
Nancy Frey and Douglas Fisher have written an excellent book that delves into the techniques teachers should have in the area of formative assessment. While it covers all types of tricks, it does spend time on the use of gestures to check for student understanding. The reviews of this text are excellent, saying it is well written and very helpful. I would suggest picking up a copy to get started using formative assessments in the classroom.
This document outlines several different methods teachers can use to check for understanding in the classroom. While not specifically about using gestures, it does suggest a "fist to five"-ometer as a method for students to say how well they understood the lesson. I think this resource is great and would be super beneficial. It includes the use of gestures, but also has many other ideas as well.
Using student gestures is a simple and easy way for teachers to check for understanding after explaining a concept. This video describes how one teacher uses gestures to evaluate the amount of learning his students attained. I think this is a great idea and would be very useful. The video does a really nice job explaining how to implement using gestures in the classroom.