9 Live Quiz TV
4Ventures for E4, 2004-5
Really very similar to Quiz TV - puzzle on screen, phone in at 60p a throw, presenter desperately trying to fill while nothing happens. 9Live seems to have done this first, in Germany, making it the Fort Boyard to Quiz TV's Crystal Maze, except that makes it sound far more exciting than it actually is.
This one was run by a subsidary of Channel 4.
Quiz Call, by the same people.
Original 9Live German website via archive.org, from October 2004.