Depending on your fitness level you may want to do a few pushups, a couple minutes of jump rope or jogging in place. These exercises are more dynamic and will help if you feel a warmup is needed. However, none of that is required.
Recently Zuzka released a video on some warm up basics, if you need someplace to start. The ZCUT DVD series also includes a guided warm-up and cool down.
My Personal Experience:
Personally I do not warm up before I ZWOW, I just jump right in.