First thanks to TMW for posting this. I'd never given it any thought before. The results are... intriguing.
Left hand:
writing,
typing (my left hand hits 3/4 of the keys - though I've been a software engineer for decades I was never taught to type),
painting with a brush (painting a wall/ceiling that is, I don't do "art"),
using a wallpaper steamer (wallpaper stripper in right hand - but see below)
Ambi:
all sports requiring a racquet (tennis, squash, badminton),
scraping ice from my car windscreen,
painting with a roller,
lifting a beer glass,
computer mouse - left handed for shoot-em-up games, right handed for work/typing.
Right:
all sports requiring a bat/stick (cricket, baseball, golf),
Using a wallpaper scrapper (with wallpaper steamer in left hand - which is why I currently have 4 sutures in my left hand - ouch!),
drinking coffee/tea/from a mug,
eating hand food (sandwiches, chocolate bars, apples).