Where Professional Models Meet Model Photographers

From the Model Mayhem FAQ:

What is a casting call?
A casting call is a post in which you can advertise a project of your own, for which you need to hire* another MM member.

*The word “hire” is used loosely here, as it does not necessarily mean that you will be paying, but it does mean that you are not expecting to be paid or that there will be any charge to participate.