I have done this activity for years, and I have learned how to handle it in 50 min. It is a bit pushy, but not impossible. However, it will be better if you can have 2 lessons in a row, or if you can't have it, the JET continues the lesson the next day.
I asked a colleague to record a video for my students. In the video, he tells my students that he is coming to Japan, but he doesn't know too much about it. He wants to know about the food, places to visit, and other things.
The goal of the lesson is for students to record a video message for my friend.
I play the video a few times, and I make sure they understand the message. Once they get it I divide the blackboard into different sections (food, places, japanese traditional games, etc). I picked some students to tell me what Japanese dishes my friend could be interested in. Same thing with the other categories. Once the board is full, I tell them to choose one item from it. They will have to introduce it to my friend on a video. Tell them to use their iPads to find a picture on the internet. Until here you should not spend more than 10-15min.
Content of the message.
The first thing I do is to demonstrate how to do it. I normally choose one item from the board, and introduce it to the students.
For example, "Gyoza is a Japanese food. It is very popular in Japan."
After that, I tell them to think of 2 phrases that describe the item. ⚠️ Very important⚠️ I tell my students that my friend has no idea of these things. So they have to explain it from the very beginning. This is to prevent students from saying "Gyoza is delicious".
Sure, but what is Gyoza? Do you see what the point is?
Once they have two sentences, I tell them to transform them into one. Let them think first! Someone will solve the problem. "Gyoza is a Japanese food that is popular in Japan." Let them practice in pairs with the item they have chosen. Pick 2 or 3 students, and check if they can do it. This is the base of the message they will record later!
Now I start adding more information (step by step). Where can we buy gyozas? Are they good?
For example, "Gyoza is a Japanese food that is popular in Japan. It is delicious. You can buy them in a convenience store or a supermarket."
Looks pretty natural right? The rest of the sentences are pretty much 1st grade grammar.
Now, I go pretty deep. From there I tell them to add present perfect which they have already studied, and another sentence expressing their opinions too. "I have eaten gyozas many times. I like fried gyozas better than boiled."
You can go as deep as you want, as long as they know the grammar. You just need to dust off the grammar you want them to use. Every time you add a phrase, let them practice with a partner while showing the picture.
If you go step by step, they will be able to record a decent video message. When they are ready, they record the message to each other. One person is recording and the other one is talking. After that switch.
This is one of my favorite lessons. The kids have fun too. And the best part is that they don't have to write anything. ONLY SPEAKING!