Years ago before our children, I did this hot pot stuff with my gf/wife. It is really pretty simple. You pretty much get any type of vegetable like bok-choi(chinese chard?), beef, pork, chicken, lamb(I've never tried this one, available in some ethnic supermarkets), you can also do some type of big fishes like salmon, seabass(ie fish that is big enough to slice). To slice meats thin, I've partially frooze it so that it is not so springy. You can also marinate the meats in a solution of soy sauce and finely chopped ginger, I usually do it the day before after slicing, but I think 20 minutes or so is suffice.
I personally enjoy my food cooked in this style in combination with uncooked green onions. I don't use oil because that stuff is just too fattening. Water is just fine. From what I understand, the french use oil, and they cook things like cheese etc.
This is done traditionally in the winter time to help keep you warm, but you can do it anytime you want.
The hard part about this is in the prepartion because you have to cut up the veggies and slice the meats thin ahead of time.
And in the end, you also drink the soup. I personally don't use a soup base because after awhile all of that food you cooked in the water, makes a very tasty soup.