This activity can be a lot of fun for students from middle school to college; it wakes the class up and gives them a chance to interact and review problem points in their vocabulary. Make sure to circulate through class, helping clear up points of confusion where necessary, and collect the vocabulary sheets before class ends. They're your "cheat sheets" for which verbs you should include in the next pop quiz or in-class exam.
With that being said, make sure you alternate activities like this one--which builds the basic, necessary skill of conjugation but doesn't use the words in a conversational context--with conversation-based activities, like playing guessing games in class.