I am a Man of Constant Sorrow by the Soggy Bottom Boys

O Brother Where Art Thou? is a great movie, and this is a great tune.. I found a couple of good versions on YouTube. This one suffers from being interrupted by a racist loudmouth. However, it more than makes up for it with the scene of said loudmouth being run out of town on a rail. I really liked the part where the men come clomping into the hall on the double carrying the rail. Just what the heck is this frieght train charging down the aisle?

This other one plays the song straight through. It has a couple of bonus bits: George (Clooney) saying Cottonmillia*, and then stumbling over the word accompanist, and the old blind guy humming / squealing to himself while the boys are singing.

IMDB (Internet Movie Data Base) page

 *well, that's what it sounded like to me.