Today, I will share with you an incident in class (upper-intermediate level), some years ago. We were reading a text about the movie "The Wizard of Oz" which was in the course book. Of course my students got really curious and asked what happens in the end and all these questions that a kid might have when they see a picture of a film! So I quickly did a small research on the Internet and showed them some trailers of the film, answered their questions about the characters, who is who, why things happened and also asked them questions about the witch and the Wizard and Doris and her friends (eliciting adjectives).
We then listened to the soundtrack of the film "somewhere over the rainbow" and I asked them to write as many words of the song as they could and try to make sentences about the film. Students had a lot of fun, working together and producing language. When they had all read their texts, I continued improvising. I remembered about a song (La la la - Naughty By ft Sam Smith) whose video clip was based on the "Wizard of OZ" story, So I played the video and asked them what this video clip had in common with the story of "Wizard of Oz". Students were very enthusiastic about it and started comparing the characters using the adjectives we elicited in the previous phase.
As homework, they had to find the story behind the video (the Bolivian legend and what this had to do with the film) I have to say that students enjoyed this very much. First of all, they didn't have to go "by the book", doing exercises and learning vocabulary. Secondly, they produced language without thinking that this was actually a lesson and the results were awesome. And last but not least, they realised how important it is to understand and use the English language if they want to learn about the world.
As I teacher I can say that I could have planned all this beforehand, but sometimes good ideas come while you are in the classroom. I don't believe that we should always be improvising, but sometimes the language you get from your students in a lesson like this is more language than if you stick to the plan. Looking forward to hear about your time when you ditched the plan.