Each student has a Styrofoam plate, a wet wipe, and a regular water cleanup (not permanent) marker. Ask students questions that can be answered in a few short phrases. They write their answers and flip over their plates. After a few moments, ask everybody to display their plates.
I have used this as a lesson review quiz and as a Lesson opener to help me determine what students already understand about a topic. When I know a little bit about what students already understand about a topic, I know where to begin our discussion.
You can also use this to have students search for answers in the scriptures, and then write them down.
Sometimes you can get real dry erase slates at the dollar store inexpensively. Styrofoam plates are inexpensive, readily available, and can be reused several times before tossing.