I use this in my Spanish 3 class. On Mondays, they are given a verb and have the homework of writing out the verb boxes. On Friday I roll a die (1=yo, 2=tú, 3=él/ella, 4=nosotros, 5=ellos and 6=student choice) and they have to complete this quiz in that form. It is really good at keeping all tenses fresh in their heads and not just the current tense we are working with. It helps them alot even though they gripe!