In Back to the Future II, Marty McFly purchases a sports almanac providing 50 years of sports statistics in the hope of gambling his way to wealth. He doesn't use it, but in an alternate timeline, Biff Tannen does. An infographic (excerpt above) from NFL Injury argues that the scheme wouldn't be profitable for several reasons.
http://nflinjury.com/the-mcfly-scheme-time-travel-sports-betting.html via Geek Tyrant