Mine happened only a few months ago. I got home from work, sat down on the couch, and felt like something was wrong with my stomach. Not... sick, per se, but not good. I decided to go to bed and sleep it off. Bad idea #1.
Then, after about a half an hour, I was certain that I was sick. Felt like I was gonna throw up, but I didn't want to believe it, so I didn't believe it, and tried to go back to sleep. Bad idea #2.
After another half hour of fruitless efforts trying to get to sleep, I sat straight up, faced the wall, and projectile vomited no less than 7 feet. Vomit. Everywhere. On the bed, the floor, the wall, the TV, everyting between me and the wall was covered. Worst part? I had spagetti for lunch, so I had to clean up chunky spagetti vomit for hours.
I actually threw up so hard I burst all the blood vessels in my face and eyes. My face looked like I had some kind of flesh-eating virus, and my eyes looked like I was a vampire.
The lessson: If you feel sick, GO TO THE FREAKING BATHROOM AND JUST THROW UP. Don't try to hold it in.