 In the episode where Jenny goes back to preschool, she tells Brad  she was only born five years ago (from their time) and Brad then  begins to list a number of events that all happened at that time.  One of these was "Super Bowl 100". Given 2004 was Super Bowl 38, and  in the show five years had passed since "Super Bowl 100", this would  make the show take place in 2071. <Add 62 to 38 to get Super Bowl  100, which makes the year 2066 (2004+62), plus five years since SB  100 makes it 2071.