This is an AWESOME film! I was lucky enough to see it twice before - once at Delaware Park and then at SilverDOCS - and I'm going again. You'll laugh, you'll cry, you'll cheer.... The Hennegans, aside from being great guys, are incredible film-makers.
Even if you're not an avid race fan, you will still get a lot out of this film. The Kentucky Derby is an internationally known sporting contest (the Queen even attended last year, for goodness sakes). No other movie shows the in-depth behind the scenes preparations that take place in getting a horse to the Derby. What also makes the movie so poignant is that it features some great scenes with ill-fated Derby winner, Barbaro. He was a true champion. The Hennegans handle his injury in the Preakness and his death with great sympathy, but they don't let it overtake the entire movie.
Go see this film if its playing near you, and if not make sure to get the DVD when its available!