If you are a STNG (Star Trek - The Next Generation) fan, you should recall the episode "Relics", where Engineer Montgomery Scott (from the original show) was rescued from a transportation buffer after being held there for many decades. Scotty then had to help the STNG crew get out of a problem concerning a Dyson Sphere. The concept of a Dyson Sphere was not a writer's plot device; it was postulated by Freeman Dyson as a incredibly huge device that would surround a star and harness it's energy.
Dr. Jason Wright of Penn State has been awarded funding from the John Templeton Foundation to use NASA's WISE (Wide-field Infrared Survey Explorer) to search for signs of these massive constructs - which would surely be a signature of a very advanced civilization. Apparently, SETI's search for radio waves is old hat these days.