Students really enjoy practicing verb forms with this powerpoint activity. It is called "Contra el Relof." On each screen there are 6 subjects with verbs and a tense (present, preterite, immediate future-aller + inf). There is a timer set to 45 seconds. Students write the correct forms either on paper or on a mini white board. When the time is up the verbs disappear and the students stop writing. All of the animation is set to do this, all the teacher has to do is click once to start. After it is done the teacher can click once more and the correct forms come on the screen. The sample has the timer set to 10 seconds, but the 10 slides in the presentation are set to 45 seconds.