Missing them
An interesting project has been initiated by a group of Israeli students to bring more world attention to the captured Israeli soldiers Ron Arad, Gilad Shalit, Ehud Goldwasser and Eldad Regev. The imagery is simple, and powerful: It documents people waiting at an airport with a blank sign.
The folks behind MissingThem.net write,

the contrast between relatives waiting for their beloved ones and meeting them, and between you, the one that stands and wait for someone you know wouldn’t come in the next flight and won’t get to meet his family is shocking. by documenting it and putting it to a designated site (and later on create more out of it) we hope that masses of photos and people participating will bring to a change in the situation
please, whenever you are in an airport and have few minutes, wait for them with an empty sign, document yourselves and send it to us at: info AT missingthem.net thank you

Check out the photos and the site.