Beep! - an engaging reading activity for any topic

For my first post, the ultimate time-efficient reading game: Beep!

It's super simple. As you read a text out loud to the class, you make deliberate mistakes e.g. you say Calcium Oxide instead of Calcium Carbonate; you swap Chile for China; you muddle etre and avoir. The students must follow along in their own copies and shout "Beep!" if/when they spot the mistake. Keep a score (you can also deduct points for premature beeping). Any one student who dominates (e.g. that sole native speaker in a class of language learners), make them the scorer or even get them to take over the reading and mistake making.

This works on many levels: for a start, it's fun in way that reading a large chunk of text often isn't. However, in order to play students must read along with you. How often do we suspect/know that half the class has drifted off while you read aloud, even if you get the students to take turns? Beep gets them reading word for word! Finally, you can of course ensure that your "mistakes" hinge on the learning and key facts you want students to get from the text. Best of all, there's no printing and zero prep time involved.

There are lots of variations to this - if you've got good ones share them below perhaps.