My absolute worst was sitting on the train - at the seats near the doors - and getting that horrible feeling. There was no where to go and before I knew it, I vomited everywhere, all over myself and all over the floor. I was only about 10 weeks so not showing at all. I am also one of those people that cries when they vomit, so it was so difficult getting the "I'm pregnant" line out. Thankfully everyone was so sweet about it. It was horrible as I was 5 stops away from my destination and everyone that hopped on the train got a great look at the contents that were once in my stomach.
I have also vomited in the middle of Flemington Markets. Then more on the way home when stopped at a red light. Oh and I vomited outside the very low fence of some poor old guy doing his gardening when on my walk to work.