The NCAA Basketball Tournament is played over a period of three weeks, usually beginning on the third Thursday in March. In the men's tournament, play starts with the "First Four," the four lowest-seeded teams fighting for a spot in the top 64. Then the real tournament begins. In the women's tournament, there are no extra teams, so there is no "opening round."
Over the first two full days of the tournament, the field of 64 teams is pared to 32. In the next two days, the field is trimmed to 16, or the Sweet 16, as it is often called. These final 16 teams take a four-day break before resuming play on the next Thursday. During the second week of the tournament, the field is trimmed from 16 to 8 (the Elite Eight) and then to four. Those teams comprise the tournament's Final Four.
In the third and final week of the tournament, the teams that survive the mayhem of March and make it to the Final Four battle it out in April for the crown of college basketball.
During March Madness, many fans fill out bracket forms to try and guess the order of the 64 teams, all the way to the winner. Sometimes, there's some money on the line. In 2017, March Madness-stricken officer workers spent an estimated $2 billion on 70 million separate office betting pools to predict the winner of the men's tournament [source: Pells]. Officially, the NCAA supports bracket contests as long as there's no entry fee to participate. Which sort of defeats the purpose.
For printable versions of the NCAA Basketball Tournament brackets, including dates and locations, visit NCAAsports.com.