Here is a great formative assessment technique-

Give every student a blank sheet of white paper.  Provide them with a question or writing prompt to respond to anonymously.  Now comes the fun part!  Tell the students to crumple up their paper and have a snowball fight (no head shots)!  Let the paper fly for a while and then ask each student to grab one snowball.  Smooth them out and ask a few students to read the responses.  Collect all of the responses so that you can review them after class.

This technique can be used in many situations where you would like to get anonymous (non-threatening) responses from students.  It can be as simple as “how is class going,” an assessment to find their initial knowledge, or a diagnostic “check up” to help you adjust your instruction.