question of the day: What movies succeed entirely on the basis of casting and performances alone?

Today’s question comes from Stingraylady, who writes:

I recently took my daughter to see Daniel Radcliff in How to Succeed in Business Without Really Trying on Broadway. He was fabulous – gave 110% and made it a really special experience for his fans. The show, however, was mediocre at best. The characters were clichés, the plot obvious, and the music forgettable. This got me thinking about movies and shows that make it completely on casting. Gladiator comes to mind. The script was ridiculous, and even the concept of a gladiator movie was absurd at the time. But I went anyway once I saw Russell Crowe in the trailer. The performances made the movie an engaging experience; snark didn’t enter in until further recollection and later viewings showed obvious plot holes and far-fetched twists. Anyway, there’s probably plenty more, and I’d be curious what others had to say.