There’s a foreign language type of activity or game called lies, where the teacher says a sentence that’s false, and students change it into a true one. You can do the activity where students speak alone or in pairs, and you can adjust the sentences to fit a target topic or grammar point. Thinking of false sentences on the fly is difficult, so bringing a list (ODT or PDF) is helpful.
An exchange might go as follows…
|Teacher:||Frogs are blue.|
|Student 1:||No, frogs are green.|
|Teacher:||Very nice. Anyone else?|
|Student 2:||No, dolphins are blue.|
This game is a good chance to reinforce the notion of multiple acceptable answers. In the above example, students can fix the sentence by changing frogs, blue, or even are.