Hi Jess -- I can honestly say that there wasn't a curriculum that I was following when I was in school to become an event planner. I just made sure that I took classes that I was interested in and I knew that once I was done with school, whatever I decided to do as my profession I would learn on the job. I know that since I've been out of school there have been "majors" or "programs" that are associated with hospitality or hotel management. You're probably wondering what does hospitality or hotel management have to do with event planning but they go hand in hand. A lot of the skill set that is involved in hotel management will help you in the event planning world - contract negotiation, food & beverage, rooming lists, sales and event management, to name a few - all part of the event world too.
However, if you do want to take some generic courses that can help you in whatever you decide to do after college, I suggest marketing and finance courses. If you are still in high school and looking into universities, I know that NYU and Cornell both have a great hotel management program.