I like to do this riddle with my students, so I'm posting it here for students and teachers.
There are 2 islands. On one island, you have a chicken, a fox, and a bag of chicken food.
You have a small boat, and the objective is to take all three items from island 1 to island 2. The problem is you can take only one item on your boat at a time.
If you leave the fox and the chicken alone, the fox will eat the chicken.
If you leave the chicken and the chicken food alone, the chicken will eat the food.
Here is a tutorial of how I do this to teach a grammar or speaking lesson. https://www.youtube.com/watch?v=0WYF8YXnpZA&t=1s
The solution is in the video as well if you need it! Let me know what you think!