From Elonka:

While I was giving my talk at CIA Headquarters in October, I managed to obtain some rubbings of the mysterious Kryptos sculpture in the main courtyard. Three of the four encoded sections on that sculpture have been cracked, but the last 97 characters are still unsolved. If this is something you're interested in working on, check this link for more information about the sculpture, as well as scans of the rubbings that I did.

CIA Kryptos Sculpture