Twice. Once I had apparently eaten something bad on segment one, and on segment two, after a lav visit, told the FA I didn't feel well (apparently I was quite pale) - but not long after the projectile departure of segment one's poison, I was fine. The other, apparently I had this happen to me. I didn't know what was going on, other than I wanted to be sick from all ends, but wasn't. I told a FA I didn't feel well (I thought I was going to pass out, etc.) - there was a paramedic in F who was sure that was what happened, they got the O2 tank out, and in about 15 minutes I was fine. This never happened to me before or after, and I spoke with my MD about it after the fact, and she said not to worry. Other than a slight headache that remained until arrival @ HNL, no worse for the wear.

In about 1.5 million miles of travel, I can't complain