From Third Way comes this clever exercise in numeracy: seeing how important various parts of the federal budget are by translating it into what you pay in taxes for each part. So you plug in all the taxes you pay, including Social Security, and it tells you what you're paying for "defense," Medicare, Medicaid, etc. What I don't know is whether they attribute the employer's portion of Social Security to you. I did so when I tried out mine. I also don't know how, or whether, they allocate corporate income taxes and federal excise taxes. My guess is that they leave these out. Still, it's an interesting exercise.
Even neater is that you can dig into the details of each budget. So, for example, you can find out how much you pay for the Iraq and Afghan wars.