I had a cool legal post to share about Congress authority to tell a guy that he can't grow his own wheat for his family (not selling it at all) because it effects interstate commerce. But I can't find what I did with my post. If I find it, I'll edit this post. I know you hope I find it and will sit and wait with baited breath until I do!
In the meantime, go read this article about the effects of Federal Spending on Education. The chart is pretty telling. Despite the ENORMOUS increase in Federal Spending, test scores and performance of students has stayed about the same.