Choose about 10 verbs from your vocabulary list and write the infinitive form of each verb on the blackboard. To one side, write a single pronoun: yo, tú, el, ella, Ud., nosotros, vosotros, Uds., ellas or ellos. Then work your way down the list, calling on a different student to conjugate the next verb for the given pronoun. You can call on students randomly or work your way down the rows, but make sure everybody gets a chance to give an answer. If a student freezes or draws a blank, let the others help him by shouting out the answer. Or for a fun riff on "Who Wants to Be a Millionaire," you can let confused students use a "lifeline" and poll the class for the correct conjugation. This keeps the entire class involved, especially in large groups where it can take a while to get to every student.
Once you feel the class has grasped how to conjugate the pronoun you're working with, erase it and replace it with a new pronoun. If you're doing an intensive review session before an exam, you might also move on to a new list of verbs. This activity works well with both non-stem-changing and stem-changing verbs.