I realize that this thread was started a while ago, but have an interesting answer to this problem. I hope that someone will find this useful!
I like using games to motivate students, so here's a way that you could incorporate a game into this type of lesson. Plus, it's easily adaptable to any topic.
What you'll need to do is create a few different scenarios and write up scripts. Include one that is "good" and two that have plenty of "mistakes". Then, have a few pairs of students act out the scenarioes. Everyone else will have to listen. After that, you can have the students get on teams to have them answer questions that you've written about the phone conversations they just witnessed.
You can add in the competition factor such as the team that gets the most right gets a bonus.
Another idea would be to have them listen to the scenarios and then give each team member a slip of paper with a sentence or phrase from the scenarios on it and they will need to determine, as a group, which ones appropriate for the situation and which ones were not. You can increase the difficulty as you go along.
Kind regards,
Shelley
Receive free games and ideas to make teaching children more fun on:
ESL games and activities for teaching English to children