Since you are teaching ESL (that means your students are currently living in an English speaking country), things are easier.
I advice you to rely strongly on excerpts from movies, TV commercials, documentaries, news from radio/TV. Play the situations on a DVD and have a discussion with them. Repeat some key scenes over and over and check their understanding. Also have them work hole play games/situations, record their speechs while they act and prepare some classes based on it.
I recommend you to read this recent thread too:
- For Teachers