This classic romantic comedy gave Jack Lemmon one of his best roles. Lemmon was ideally cast as an ambitious clerk in a big insurance company trying to gain promotion by renting out his apartment to senior executives for their extra-marital trysts. Everything goes according to plan until Lemmon falls in love with elevator operator Shirley Maclaine - and discovers that she is the mistress of his boss Fred MacMurray. The three central performances were perfect and Lemmon and Maclaine both received well deserved Oscar nominations. This multi-award winning movie is one to be seen again and again.