Xbox Live Primetime was first announced by Robert Bach, the then head of Xbox 360 operations, at Microsoft's 2009 CES keynote. The service was largely intended to be themed around video game versions of popular TV gameshows. Much like TV shows themselves the service was intended to run over a number of "seasons" and would offer players real prizes for winning.
The first and only game released for Live Primetime was Microsoft Studio's 1 vs. 100 which ran for two seasons. On July 15th 2010 Microsoft announced that there would not be a third season of 1 vs. 100 and have expressed no plans to continue the Primetime service since.