http://www.treasurydirect.gov/govt/resources/faq/faq_publicdebt.htm#DebtFinance
From that site:
“You can write a check payable to, "Bureau of the Public Debt," and in the memo section, notate, “A Gift to reduce the Debt Held by the Public.” Mail to:
Attn Dept G
Bureau of the Public Debt
P. O. Box 2188
Parkersburg, WV 26106-2188
This site--101American.com—hopes to reach others willing to pay their fair share, and also grateful enough for the U.S.A. to pay an extra 1% over federal tax. (I had wanted the site named 101%American.com, but you can’t use a percent sign.)
My contribution is like a grain of sand on Coney Island Beach, but it’s a stand against the seditious greed-mad Tea Party, unwilling to pay anything to live in the greatest country in the world. My check goes out today.
There are buttons: “Proud to Pay for the USA.” Anyone willing to wear one, just ask. Free. Postage paid.