Icebreakers are a very yesterday tool. Facilitators who use icebreakers operate from a flawed theory of presenting. They think they need to use the first few minutes of their time building rapport and getting the folks in the room "warmed-up" to each other, the content and the presenter. This doesn't work.
A better theory is based on the fact that we have about 30-seconds to get buy-in from an audience member. This means that the "warming-up" needs to happen even before we officially begin - to maximize the power and effectiveness of those first, critical 30-seconds. In the classroom, this is called "bell work." This means you have something for the students to do from the moment they walk into the classroom, even before the bell rings and class officially starts. Here are a few techniques I use in my programs to get the audience members started even before I start...
Have music playing
Arrange the seating so they are forced to sit next to someone
Have an engaging question on a PowerPoint or easel pad
Have a set of engaging questions in a PowerPoint show (have the slides change every 5-10 seconds)
Get in the audience members' zone - roam the room, ask questions, listen
Give the audience an actual task to perform before the workshop starts - and make sure it is something that "laters" can do as they slowly stroll in
Most importantly, be in control of what the room feels like, looks like, and acts like even before you officially start!