The only way I can think to describe a formal or informal would be like a college prom, only more fun. Formal is the most formal social event you will have, and informal is just a less fancy version of formal that is usually themed. Formal and informal are nicer events than a mixer or date party so it is usually more expensive. Because they are more expensive you sometimes have to buy tickets to cover the cost of catering, the hotel, and in some cases alcohol.
Formals and informals are different from normal social events because they are held at nicer venues like hotels. They also have caterers the provide a full meal and drinks. Also at these there is usually a bar for guests and sisters that are 21 or older. It takes a lot more effort to plan formal and informal because you have to book a hotel, catering, dj, plan a theme and provide some sort of entertainment other than the DJ. These events are like a college prom because the night is set up basically the same. You sit down at tables with other girls and their dates and you eat, dance, and there are awards like sister of the year and things like that.
There are also honor guards at these events, but they seemto be less strict at informal and informal.
Sorority Life 