Created by J. Michael Shaughnessy and Thomas Dick, this activity presents a version of a classic game-show scenario. You pick one of three doors in hopes of winning the prize. The host opens one of the two remaining doors which reveals no prize, then asks if you wish to "stick or switch." Which choice gives you the best chance to win? The approach in this activity runs from guesses to experiments to computer simulations (links to applets are provided) to theoretical models. The activity can be adapted by leaving out the "flip-a-coin" strategy presented here. This is a fun and worthwhile activity that students can easily engage with.