21 is a 2008 American heist drama film directed by Robert Luketic and stars Jim Sturgess, Kevin Spacey, Laurence Fishburne, Kate Bosworth, Liza Lapira, Jacob Pitts, and Aaron Yoo. The film is inspired by the true story of the MIT Blackjack Team as told in Bringing Down the House, the best-selling book by Ben Mezrich. Despite its largely mixed reviews and controversy over the film's casting choices, 21 was a box office success, and was the number one film in the United States and Canada during its first and second weekends of release.

Massachusetts Institute of Technology (MIT) senior math major Ben Campbell (Jim Sturgess) is accepted into Harvard Medical School but cannot afford the $300,000 fee. Despite a 44 MCAT score and top grades, Ben faces a fierce competition for the prestigious Robinson Scholarship that would pay entirely for the medical school. The director tells him that the scholarship would go to the student who would "dazzle" him.

At MIT, professor Micky Rosa (Kevin Spacey) challenges Campbell with the Monty Hall problem, which he solves successfully. After looking at Campbell's score on his latest non-linear equations paper, on which he got 97%, Rosa invites Campbell to join his blackjack team, which consists of fellow students Choi, Fisher, Jill, and Kianna. Despite being told by Rosa that he had already gotten into the Harvard Medical School, Campbell refuses to join the team on the premise he had been promoted at his job. Next day, Jill visits Campbell at his job and attempts to coax him into joining the team. The system involves card counting and the team is split into two groups. "Spotters" play the minimum bet and keep track of the count. They send secret signals to the "big players", who place large bets whenever the count at a table is favorable. Campbell reluctantly joins the team, telling Rosa he is only doing so until he can pay for medical school.