Don't listen to a certain moron who shall remain nameless.
Ideas:
--Custom Barbie clothing:
I once went to an event where a bunch of vendors gathered and sold their own crafts at a park. I walked by a booth, and some ladies were selling really cute, one-of-a-kind Barbie doll dresses that they had made themselves, one particular dress was $10, it was a simple full skirted dress gathered at the waist with little beads dangling off. Keep in mind, make quality clothing as nobody will pay for something poorly done. Make sure the seams/hems are securely sewn. Barbie doll accessories can make you a pretty good profit, I always have people ask me if I sell my doll clothing and customized dolls.
--Poppets (Commonly referred to as "Voodoo dolls"--not the same!):
You can make these different sizes and stuff them with scrap cloth or cotton.
They are pretty easy to make as you just have to cut them in a gingerbread-man shape. Oddly, the more crudely you cut them, the cuter they look. Sew different sized buttons for eyes and you can add a smile/frown (Do these two steps before sewing both pieces together, sew the two pieces together from the outside, stuff when you reach the head). You can add yarn for hair too, but bald ones are cute. You can also make simple nooses and hang them on something (hanger, tree, stick, etc.) where people can see them and choose.
Selling point for poppets:
They can be used as book marks (if they are tied with a noose), they can be hanged on a cealing/window (stringed together), and they are sleeper-friendly.
*I make these every now and then and people at school think they are adorable and always beg for me to sell them one. You can make small ones (palm-sized) for $5+ as you go up in size. I swear they'll sell!
--Any artists?
You can sell drawings/paintings, the more colorful, and crazy, the better. They don't necessarily have to be Michelangelo, just something that looks fun and cool like something that has a Tim Burton feel to it.
* For all of the above, keep in mind that people like genuine work, it will draw their attention.
--Food
Brownies, candy, cupcakes, etc.
(There's a girl at school who buys cupcake mix for a single dollar, she makes forty and sells them for a dollar each. Really good profit!)