O Brother where art thou impresses with its storyline set in the American deep south, as it takes a comical look at the Bible thumping segregationist populace of Mississippi in the first half of the 20th century. George Clooney as the Dapper Dan wearing convict and George Turturro as the convict who always has to oppose Clooneys suggestions particularly impress.
The movie has a lot of characters from Homers Odyssey, like The Sirens, Cyclops and of course Clooneys name in the movie is Ulysses which is Odysseus. I would definitely recommend some reading on them to appreciate the digs the storywriters take at them.
Even Satan makes an appearance as a jail warden with his bloodhounds and the movie ends with a biblical version of the apocalypse. Holly Hunter as George Clooneys estranged wife is also good, although nowhere near as impressive as her role in Broadcast News.
The soundtrack of the movie is simply awesome, with a lot of legendary blues singers contributing to it. One of the reasons to buy the DVD / atleast buy the soundtrack of the movie on CD. John Goodman seems to be made for the role of Cyclops and the women as The Sirens are simply as beautiful as a siren can possibly be.
Its a very well written script which depicts the general social structure of pre world war II south with generous doses of the KKK and of course one of the funniest part of it was a common enough joke about selling your soul to the devil at junction of four roads, so that you can play the guitar really well. The best part of the movie is that it takes a bemused look at the culture of the south at that time, unlike some serious movies like As Summers Die or Mississippi Burning