Casual-Fans are fans who aren't particularly into their fandom. They enjoy it, know some trivia, see some movies, have some stuff. Casual-Fans are more laid back.
Note: It is possible to be a Casual-Fan in one area, and a Proper-Fan in another. Or a Casual-Fan and a Psuedo-Fan, etc, etc.
Beth is a Casual-Fan of Star Wars, but a Proper-Fan of Star Trek. Things Star Wars Proper-Fans get annoyed about don't bother Beth, at least not enough to whine about.
A person who enjoys the act of tailgating more than the sport itself. In many cases, the casual fan knows nothing about the actual sport being observed. This often results in the misuse of sport terminology, mispronounciation of athlete names, and overall confusion with rally cries.
Girl: "I just overheard Billy ask how many lay-ups Brett Favre has made."
Guy: "That's typical for a casual fan like him."