Exit Slips, or exit tickets are a WONDERFUL way of assessing student comprehension. Since they are used in gen ed classes, students who learn how to write them in the SDC also "fit in" better when mainstreamed if they know the expectation.
Exit slips can take on many forms (see link below)
For my students, I allowed them to draw or write what they learned, and made this an expectation at the end of every class. You can see some of the exit slips students completed during my slide show!