STS-126 NASA Control Center UFO
The unknown object can be seen on the Mission Control Center TV screen (Houston, Texas), between 0:27, when it suddenly starts to move and 1:04 minutes into the video, when it leaves the screen at the bottom left corner.
The TV screen footage is either a NASA video transmission from the Space Shuttle or ISS. In any case, this is footage from Space and the video shows an object, which seemingly hovers and then starts to move.
Judging by the path of the object, you can safely rule out that this could be Space debris:
http://www.youtube.com/watch?v=AFBrzx8qsO4
