More ideas, since I'm into it now:
1920's:
Hair: bobbed hairstyles (lots of variations of this), Dutch boy cuts, finger waves, eton crops with or without kiss curls, lots of fun headbands and hats
Clothing: feathered headpieces, drop waist gowns and flapper dresses, fans, jazz suits, knickerbockers, riding boots, Ivy League look styles, two-toned oxford shoes... garter belts, turban hats, long pearl necklaces
Food: deviled eggs, codfish cakes, chicken ala king, lobster canapes, pineapple upside-down cake
Decor: 1920's build items to create cool speakeasy-type nightclubs or Great Gatsby-type parties
Toys: adaptations of the Raggedy Ann doll (imagination), Tinkertoys (mental), and yo-yos (motor)
Gameplay: "Swanky parties" social events (styled like Great Gatsby parties), and the addition of baseball in the game (shoutout to Babe Ruth)... they could make baseball diamonds on a big grid and have kids and adults run to different bases or swing a bat at a ball. Or they could just have a play catch feature just with a glove and ball, sort of like how the soccer ball works.
Other: Charleston dance, 1920's jazz radio station, silent films added to the movies with actors who resemble Charlie Chaplin, Josephine Baker, Clara Bow and the like.
