You could write about how pimpin' the 1920s were. Rollin' like Gatsby.
Or some obscure thing, like I quickly looked at the Wikipedia article for the 1920s, and there's some war I've never heard about (or at least can't remember):
Edit: Or something that would be cool would be to examine the use of cartoons as propaganda in wartime. For example, in my history class last week we watched this Donald Duck cartoon from WWII, and I thought it was hilarious.
Thanks for all the ideas everyone. Regardless of what I choose, I definitely need to find a way to incorporate those cartoons though >_> Man those are great.