Libertalia is the name given to a planned utopian society founded by pirates. This utopia was founded on a socialist foundation a century before Karl Marx ever put a word down on paper. The story of a pirate-socialist-utopian society is a fun topic for a speech by itself, but would really come to life if you are allowed to dress in character for your speech and you arrived dressed in full buccaneer regalia.
A demonstrative speech about belly dancing should be fun enough to immediately draw the attention of several members of your audience. If you can supply visual aid and are allowed to show off belly-dancing skills (or lack thereof), then this speech topic becomes very much fun for all involved.
The history of emoticons isn't long and presents the opportunity to educate people who may use something everyday without knowing anything of its history. A speech on emoticons is a choice for a speech that requires a slideshow presentation. The history of emoticons is a good informative topic, but you could also use this as a how-to speech and even a persuasive speech taking pro or con on the concept of how these little images affect communication.
Take your mad skills on the skateboard and transform it into a how-to speech topic in which you explain the history behind certain moves. Then lay down your board and show off some of the skills that you have or will be talking about.
Prepare a speech that looks into the short but fascinating history of fads. American fads have ranged from swallowing goldfish and sitting atop a flagpole to streaking and Pet Rocks. When it comes to fads, you certainly won't have to spend a great deal of time looking for ideas. Fad topic speeches could explain how the fad developed of it could focus on the recurring influence of fads on modern society.
If your audience is mature enough, a duo could give a speech on the proper way to lace a corset. Obviously, the corset would be displayed over a T-shirt or other clothing. If the assignment is for one person to give the speech while demonstrating how to do something, this could become a viable speech topic for two women or a male/female couple. Of course, it would be fun for completely different reasons if two men did this.