Charlie Kaufman is known for writing interesting scripts (Being John Malkovich, Eternal Sunshine of the Spotless Mind), so Synecdoche, New York was bound to be another, plus he directed it.
The movie follows Cadin (Philip Seymour Hoffman), an aging theater director who is convinced he is slowly dying. Through his many relationships with his wife (Catherine Keener), the box office attendant at the theater (Samantha Morton) and a young actress (Michelle Williams), Cadin's journey through life leads him to create his final piece, a large scale play about his life.
But, the catch is that every day of life lends itself to a new page in the play. He purchases a huge warehouse and builds a lifesize replica of New York. He hires hundreds of actors to continuously play these characters, one of whom stops Cadin at one point and asks, "When are we going to get an audience in here? It's been 17 years." There are actors hired to play the characters, then there are actors hired to play those actors, playing the characters.
It's an incredibly twisted story. It's got beautiful music. It's got stellar performances by the entire cast (my favorite was Morton's).
Definitely worth seeing. It's now available on DVD. My suggestion would be to watch it more than once, just like Eternal Sunshine.