All males in the United States born between 1872 and 1900 were required by law to register for the draft. Out of the 24 million World War I Draft Registration Cards, here are 50 of the most famous, infamous, and interesting, as compiled by the National Archives: Link - via Boing Boing
This one above is the draft card of Harry Houdini, who signed his middle name as "Handcuff"!
How the times have changed.