Wouldn't use uranium, because as another poster mentions it's more a novelty and there are better materials you could use, but you could make your own cloud chamber to observe radioactive decay with the naked eye. Makes for a really cool science demonstration :)
There isn't a whole lot you can do with it, you are basically getting a rock. You can show it is radioactive by running a geiger counter across it. Interestingly enough the old rare earth mine in Nevada, back when it was closed and essentially "abandoned" had a variety of radioactive materials in its tailings (the most common being Thorium) we did a science trip once to grab some and figure out the various isotopes in it.
If you put it in an air tight container you can collect Radon.
You probably have a more radioactive americium source in each of your smoke detectors than in that entire jar.