The American Math Competition, AMC, open to any high school student, is the first round of a series of competitions that are used to select the US team for the International Math Olympiad and to develop mathematical talent. The dates are Wednesday, November 10 and Tuesday November 16 and you can choose either or both of them, but you will need to be able to clear an hour and a half in the afternoon.
If your interest is piqued, but you can’t make these, the Math Club meets every Sunday at 4:30 in Koch 315, and new members are always welcome!