1990s

These events happened in the 1990s:

The Big Bang Theory

 * 1991: Sheldon starts college at age 11
 * 1994: Sheldon graduates from college at age 14
 * 1994: Sheldon's father dies
 * 1995: Sheldon attends Comic-Con to meet Wil Wheaton; when Wil doesn't show up, this fuels Sheldon's longtime hatred for him.
 * 1996: Sheldon receives his doctorate.
 * 1997-1998: Penny rebuilds a tractor engine all by herself at age 12