After my nephew's 3rd birthday party, a year ago. I drank too much fizzy stuff, I think. It was very embarrassing, though; I felt like a 6-year-old.
Actual tummy bug sick, I think most recent was about 3 years ago. I have a bad fear of vomiting, which made it worse. Time before that was November 2008 (Remembrance Sunday, in fact). Before that it had been absolutely years.