Try this show on big classes.
The super-sized class is always a daunting task. How do you teach a group of 60? http://www.eslteachertalk.com/2006/1...g-big-classes/
There are a lot of ideas there.
Here's an older thread from these forums
Does anyone know some good activities for large classes?
Here's a thread from Dave's ESL cafe
http://www.eslcafe.com/forums/teache...pic.php?t=1222