Warning: the following exercises are not scientifically proven to cure burnout, but they are definitely entertaining.
Try to find the humor in a situation where you're not actually doing anything productive. For example, spend 30 minutes watching cat videos while simultaneously pretending to work.
Practice saying the opposite of what you mean. For example, if you're feeling exhausted, say you're 'feeling refreshed' and 'ready to tackle any task'.
Learn to appreciate the beauty of doing nothing. Take a 30-minute break to stare out the window and contemplate the meaning of life.