The Mathematical Association of America (MAA) will host a national conference on August 2-4, 2012, in Madison, Wisconsin. It seems it is a big event that I had not been aware of; the website mentions that 1, 535 participants were present last year.
While the registration price seems to be exorbitant for institutions, I would say the Graduate Student price is rather reasonable ($50). Also, discounts are offered for reservations at the Hilton Madison Hotel and Sheraton Madison Hotel; for a cheaper price, the Madison Smith Hall at the UW-Madison has available rooms for the conference.
Take a look. I hope to see some of you over there.