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