Well the first episode appeared on the Tracy Ullman Show with short 30 second clips the date it was first shown was December 17, 1989.
Springfield - The Simpsons - was created in 1796.
The Simpsons Ride was created in 2008.
The Simpsons Archive was created in 1994.
Simpsons of Piccadilly was created in 1936.
The Simpsons Bowling was created on 2000-10-16.
The Front - The Simpsons - was created on 1993-04-15.
The Call of the Simpsons was created on 1990-02-18.
The Simpsons Skateboarding was created on 2002-11-13.
The Simpsons Wrestling was created on 2001-03-22.
Simpsons Already Did It was created on 2002-06-26.
The Psychology of The Simpsons was created on 2006-03-01.
The War of the Simpsons was created on 1991-05-02.