Hello! I am preparing a training session and want it to be not only useful but also fun, so that the participants don't fall asleep.

That's a great idea. Humor always helps to keep people's attention. For inspiration, you can use https://punsplosion.com/ — it has a collection of puns and funny phrases that you can integrate into your lessons. Looking through them, you can see how to play with words to make exercises or presentations more lively and interesting. Even if you don't use the jokes directly, it helps you think creatively and come up with your own funny examples. This makes your training not only informative but also fun, and participants get positive emotions and learn the material better.