Federal Reserve notes were originally backed by gold; now they're just paper, not backed up by tangible assets. Because things are set up this way, all our money represents debt, and we can never pay it off because the more money we have, the more debt we have. Our tax dollars go to the Fed, but they're not really an asset since they're repayment of debt created when the the government buys its own money at interest.
The Federal Reserve was created by Woodrow Wilson in 1913 and stripped congress of the control of our money. From the name, people think it's part of the government. It isn't. It's a corporation of banks and it's completely unconstitutional.
If you feel like spending Sunday with your hair standing on end, keep reading about this.
Congressman McFadden's Remarks to Congress, 1934
links to lots of articles pro and con
links to Ron Paul's speeches about the Fed, the economy and monetery policy