Hep A is what used to be called infectious hepatitis -- it is a low mortality, short-incubation, mild form of the disease. It is primarily transmitted through the fecal-oral route, meaning people need to wash their hands more often. Primary at-risk populations include travelers, children in daycare, large institutionalized populations (eg, prisonners), and people who eat raw shellfish. Outbreaks of Hep A caused by exposure to contaimnated food or water are fairly common. You can be vaccinated against Hep A.
Hep B used to be known as serum hepatitis. It's a low mortality, long incubating, moderate disease, transmitted by sexual contact, needlestick, or exposure to contaimnated bodily fluids -- it's a lot like HIV in this sense. Vaccinations against Hep B are effective and widely available, although the usual course takes six months and a series of three injections before you're fully protected. (A "rapid protection schedule" is also available.) They're good for five years, so when Jeanie says, "I had one five or six years ago," it means she's got another one due shortly.
Hep C is a mild, low mortality form of hepatitis that has an uncertain and variable incubation period. It wasn't identified until around 1989 when a good test was finally developed for the disease; many people who have Hep C got it through blood transfusions before blood banks started screening donor units for Hep C in 1990. It is primarily spread by parenteral contact, although there's speculation that it can be spread through sexual contact as well.