I have done 3 crossfit workouts now. I have not puked or even come close. On occasions I have puked before, I can think of 3-4 times. Each occasion had stimuli far different from a normal workout.
USMC Recon Indoc - Firemans carry up radar Hill in KMCAS, Hi. Obviously I was not going to stop, and I was not going to drop a team member - period.
1 week all you can train at the Torrance Gracie academy, back in the late 90's. Too much volume over time, but since I had paid for the week and privates - I went as hard as I could.
Boulder, Boulder 10K. Time bet between several guys. Made my time, but puked for 30 minutes when it was over.
There may have been 1 more time, but I dont recall the details.