Explain that you are going to practice each other's names. Therefore it's very important that they listen and make eye contact with people who are speaking.
You go first; say your name and then hand the ball off, rotating the ball clockwise around the circle. The next student says your name, his name, and then hands off the ball to the next student. That student says your name, the previous student's name, and then his name. Proceed in this pattern around the circle. Allow the students to help each other remember the names.
Now, sitting in the same circle, roll the ball to a student. She should say your name and then her name. She should then roll the ball towards another student, saying that student's name. Continue this until everyone has been named.
Have the students stand up and scramble the circle. Try remembering everyone's name with one of the above procedures.