Flagpole Sitting
Started by Alvin "Shipwreck" Kelly who was a professional stuntman. He did it on a dare in 1924, and it soon caught on nationwide. It became a spectator sport, and he eventually set the World Record at 49 days with a crowd of 20,000 people watching. When the stock market crashed in 1929 and the Great Depression started, it brought an end to this fad.
Conk hairdo
Originated in the 1920's and was popularized by Cab Calloway. Started by the African American males trying to straighten their hair, the conk was the end result.
Flappers
They smoked, drank, danced, and voted. Flappers broke away conservative image of womanhood that prevailed at the time. They wore short hair, wore less clothing so they could move freely, used make-up, and created the concept of dating. They were giddy, unconventional, and took risks. In 1929, the stock market crashed, the great depression started. and the frivolity and recklessness of flappers came to an end.

Freudianism
America took psychoanalysis to the next level with games of personalities and ridiculous theories based on those of Sigmund Freud.
Mahjongg
China conquered the United States as millions of Americans took to the mahjongg tables to Pong and Chow their way to, well, a really big fad.
Cloche hat
(deriving its name from the French word for "bell") became a necessity for daytime wear. The small hat fit snuggly over short hair and almost reached to the eyebrows. It was often decorated with a pin in the front or a ribbon.
Pez
- In 1927, Eduard Haas, an Austrian candy executive, developed a small candy mint which he called PEZ (short for pfefferminz, the German word for peppermint). The peppermint candies were stored in a small tin and sold fairly well for more than 20 years. Initially it was marketed as a tasty alternative to cigarettes for adults attempting to quit smoking.
In an effort to boost sales and develop a brand identity for the PEZ mints, the first pez dispensers were introduced in 1948. The original dispensers did not have the trademark heads, which were introduced four years later. These dispensers had cartoon heads and became very popular with children who traded them back and forth. These early dispensers are now very much in demand and are valued treasures among collectors.
More than 3 billion PEZ candies are consumed each year and more than 300dispensers have been issued.
Dance Marathons
People loved to dance, especially the Charleston, Fox trot, and the shimmy. Dance marathons were something everyone went to every weekend. The longest dance record ever recorded was a record of 3 weeks of dancing.