The Apartment (1960)

Jack Lemmon climbs the corporate ladder by allowing the higher ups to use his apartment as their rendezvous pad with their mistresses. Until he finds true love. Directed by Billy Wilder.

A classic Wilder, sweet and cynical, about C.C. Baxter (Lemmon), a lowly schlup at an insurance company who climbs the corporate ladder by whoring his apartment out. He's a pushover, and anxious to get promoted, which allows the higher ups to walk all over him. They book his apartment so that they have a place to bring their mistresses, which also has the effect of making Lemmon's neighbors think he's a real ladies man. But the one girl who turns Lemmon's head is the elevator operator played by Shirley MacLaine.

The only problem is that when the head of the company (Fred MacMurray) finds out about what's been going on, he pretty much takes over the booking of Lemmon's apartment (much to the annoyance of the other guys who had been using it). The only problem is that MacMurray has been bringing MacLaine there. When Lemmon finds out, he's infuriated, but still allows it to go on. But when MacLaine attempts to commit suicide there after being jilted by MacMurray, he comes around. Eventually, so does she (after the mandatory growth of the character).

It's certainly a cynical look at the corporate world (want to get ahead? rent out your apartment as a love nest!), but at the same time the sweetness between Lemmon and MacLaine is a counter to this world view. Lemmon eventually has to figure out that climbing the corporate ladder may not be worth it for him. Fantastic Wilder, and great performances (especially from Lemmon).