If you want to learn how to be funny on celluloid, you need to watch something by Preston Sturges. Sturges, Hollywood's first writer/director, came from the theater and later the typically anonymous salt miles known as the Writer's Guild. He was known for his talent with words. But the man could direct. He was particularly bold with long takes and fluid camera movements; the sorts of tracking shots that tell jokes without dialogue.
Here is a perfect example. First, an innocuous establishing shot:
Now the camera zooms out as we see Trudy (Betty Hutton) partaking of some Victory Lemonade as a party rages all around her.
Just as she takes a sip we note the ramifications of a lemonade without sugar and, almost clairvoyantly, Sturges provides the punchline.
The rest of the movie is just as delightful. Trudy, whose last name is, ahem, "Kockenlocker," spends a wild night on the town with a platoon's worth of departing troops. A bit too much Victory Lemonade, a konk on the head, and Trudy doesn't remember much more than the following fact: somewhere along the line she married one of the men in uniform. Then a revelation: she's pregnant, too.
Racy stuff for 1944 at the height of the power of the Hays Office, and Sturges dances around the Code's restrictions like a batam around a heavyweight. The whole notion of an absentee husband and father is basically a device to allow Sturges to make a comedy about an unwed mother, and he ridicules that device over and over (the vaguely remembered gent's name is "Ratsky-Watsky"). A how-to guide to making funny movies and annoying prudes, courtesy of Preston Sturges.