If they won't try it, HIDE it!
My kids can be picky when it comes to eating their veggies, so instead of unsuccessfully convincing them to try it, I just hide them in my meals. Any veggie I want to add to a stew or sauce, I puree in the food processor. This makes for a nice hearty & flavorful gravy or stock. They never see it, but are getting all the nutrients & flavor.
What trick do you have to get your family to eat something they may not like?