The thought of role play sessions on training courses often makes the blood run cold, especially when it is employed to teach soft skills. I remember doing a course on phone skills when the trainer recorded role play phone calls.
Unfortunately, she played them back to the whole class, which many of the candidates found embarrassing and humiliating. What most candidates took away from the course was a sense of anger and resistance. Role play can be good if you are trying to teach a class about technology, and you can have a great deal of fun in the process.
Let me describe a lesson that I ran at a college some years back. A student had asked how a modem worked and I started with drawings on the board. By the end of the lesson however, we had started the role play. One student was the display, with a marker pen and a dry wipe board. The next student had a copy of the ASCII code set, marked with the binary equivalent. Across the room were two more similarly equipped students.
It came down to a student squealing high and low notes, another one writing down the squeals as zeros and ones, then looking the numbers up and writing the message on the board. It took ages to transmit "Hello" but we covered handshaking, protocol negotiation, binary numbers, error correction, and uncontrollable laughter.
It was an entirely impromptu session from which we all gained a good understanding of communication theory; it was a little unconventional, which led to questions being asked by the head of department about my methods, but I felt entirely justified in my approach and would use it again if required.
It was less stuffy than the normal approach, and I am sure that those who participated in the session will remember it. I use a similar approach when I describe things like CDMA, where I use the analogy of a chocolate cake to explain the sampling process.