'The Odd Couple' (1968)
Lemmon and Matthau were the ultimate comedy team, starring in 10 movies together. Billy Wilder's 'The Fortune Cookie' introduced us to their conniving ways, with Matthau garnering an Oscar for his role as a sleazy lawyer.
Lemmon always played the neurotic nut forever agonised by Matthau's sloppy approach to life. 'Grumpy Old Men' helped them find a modern audience but they'll never top their work in 'The Odd Couple'.