Its not often that you'll hear me say this, since its a rare thing for it to occur, but I was wrong. A few weeks back The Girl and I were down to the Wal-Marts where I had the song Particle Man stuck in my head, which led to an argument on whether or not Istanbul (Not Constaninople) was a They Might Be Giants song or an old song from the 40s. While she had never heard the TMBG version, she had heard it performed in the movie Mona Lisa Smile and insisted it was an old song. Being the hardheaded music snob that I am, I was unwilling to concede that I might be wrong without proof, and so here it is. According to Wikipedia:

Istanbul (Not Constantinople) is a swing-style song, written by Jimmy Kennedy and Nat Simon. It is based on the music for "Puttin' on the Ritz", written by Irving Berlin in 1929. It was originally performed by The Four Lads in a recording made on August 12, 1953.

Anyway, I was wrong, she was right, and here's the video of the TMBG version taken from Tiny Toon Adventures: