Did you know?

The "official" CrossFit Warm-up is in the April 2003 CrossFit Journal.

3 rounds of 10-15 reps of
Samson Stretch (do the Samson Stretch once each round for 15-30 seconds)
Overhead Squat with broomstick
Sit-up
Back-extension
Pull-up
DipNote that for a workout that's dip or pullup-centric, you might want to do something else in the warmup.

Things have come a long way since 2003, but I think they got it right from the start. I've been training with crossfit for almost 4 years and have come up with my own warm-up that works for me.