Using your fingers, draw a simple picture or write a message on the back of your student and ask him to figure out what you are drawing. Take turns. Now try writing messages in the palm of your student's hand for him to guess.
Using any raised texture (like glitter glue or even crayon), draw or write messages or pictures that the student will try to guess by just using his fingers to feel what you've written. I have always wanted to use Braille for this but haven't yet.