I found this review activity on Pinterest (posted by Mrs. Gilchrist, who decorated her Power Tower cans nicely), originally found on Teachertipster.com. The idea takes advantage of many kids' fondness for cup stacking. The "Power Towers" are merely Pringles cans that house paper cups used for stacking. Watch the video as a teacher explains that you can write review questions on the cups to help students with quick recall of facts, like math questions, sight words or vocabulary. If kids could recall multiplication facts as half as I've seen some cup stackers, they'd be a marvel!