STS-115 Space Shuttle Atlantis blasts off from Kennedy Space Center Florida. Near the end of the clip you can see the vapor cloud as the shuttle breaks the sound barrier. This was shot by a good friend of mine, he was kind enough to get me that close to the pad, then run the camera as I watched.

EDIT: Yes, I know it's a singularity cloud. We've been over this several times in the comments. (less info)