There's a campaign that's been started to put the face of a woman on the US $20 bill by the year 2020 (which will be the 100th anniversary of women's suffrage in the U.S.)
http://www.womenon20s.org/
You will have a chance to select three women candidates & then you will be contacted later when it comes down to their final "election". Then a petition will be sent.
Its a very interesting idea. The U.S. Mint put Susan B. Anthony & Sacajawea on $1 coins (too much like size of a quarter) & those went nowhere but $20.00 bills might go everywhere.