The Centers for Disease Control and Prevention released their most recent cancer data a few days ago. It's the numbers for 2010, which feels dated. However, the annual data goes back to 1999, across demographics and states, which makes this data worth a look. You can download the delimited files here.
A browser accompanies the release, as shown below. It's really just that though, leaving analysis up to you, and it's rough around the edges.
So if you're looking for a weekend project, this is a good place to go. I'd probably start with the age breakdowns and work from there.