What's Eating Gilbert Grape is a 1993 film adaptation of a book by the same name written in 1991. The same guy who wrote the book wrote the screenplay for the film, Peter Hedges. The movie stars Johnny Depp, Leonardo DiCaprio, Juliette Lewis, and Darlene Cates, but I will skip the synopsis :)
First off, I'm not really the biggest fan of Johnny Depp - I loved Edward Scissorhands, and thought the first Pirates of the Caribbean was okay, but other than that, not a big fan. This and Edward are definitely the exceptions; I think he was perfect for this movie.
Leonardo DiCaprio on the other hand, I am a fan of - but even still, this movie stands out to truly show his talent, and is my favorite of his as well as Mr. Depp's. He is completely believable the entire movie which really allows you to get sucked into it.
I also don't much care for Juliette Lewis, but the only thing in this movie that really bothered me about her was her short hair, haha. Yeah she was supposed to be a bit eccentric and different, but I just don't dig the short hair on girls look at all.
Anyhow, the movie itself is amazing and comes highly recommended. It's not just me either, it is "certified fresh" by Rotten Tomatoes at 89% positive reviews, as well as carrying an average score of 7.8/10 on IMDb.com. Personally it's in my top 10 all-time list. It might be a little too slow for some viewers, it takes place in a small town in Iowa and has that feel about it, but if you're not immediately turned away by such, I think you will enjoy it.
You can get it here on Amazon for about $5 on DVD, or they have it available on Amazon Instant Video to rent or buy, starting at $2.99. Well worth it guys, well worth it.