If congress can actually improve the economy with a stimulus package, then why shouldn't it pass a stimulus package every year, month, week, or day?
The answer, of course, is that congress cannot actually improve the economy unless it stands out of the way.
That's right. The best stimulus package is no stimulus package and an unwillingness to meddle in economic matters.
It seems counter-intuitive that doing nothing is in fact doing something, but consider if everything that you do is wrong, then doing nothing is a good idea.