- The application of energy to something to create an internal state of excitement, particularly through electric, magnetic or thermal charges.
- The act of becoming excited (eg. sexually).
Season 3, Episode 23 - The Lunar Excitation
Aired May 24, 2010
After Penny grows tired of her dim-witted date, she worries that dating Leonard has ruined her for dating normal guys. Meanwhile, Wolowitz and Koothrappali conspire to find Sheldon's perfect match online.
Season 4, Episode 8 - The 21-Second Excitation
Aired November 11, 2010
The guys camp out to attend a screening of Raiders of the Lost Ark featuring 21 seconds of never-before-seen footage. When the guys find themselves at the back of the line, Sheldon is given another reason to hate his nemesis Wil Wheaton. Meanwhile, Penny's girl night with Bernadette turns into a slumber party when Amy invites herself along.
Season 5, Episode 21 - The Hawking Excitation
Aired April 5, 2012
Howard is working with Professor Stephen Hawking and, knowing how much Sheldon admires him, is going to let Sheldon meet him. When Sheldon is yet again rude and condescending towards Howard, he decides to have some fun before introducing Sheldon to Professor Hawking.
Season 6, Episode 5 - The Holographic Excitation
Aired October 25, 2012
While Raj helps Stuart with the annual Halloween party at the comic book store, Sheldon and Amy are divided over their couples costume. Meanwhile, Penny takes a greater interest in Leonard's work, while Howard annoys his friends by constantly talking about his trip to space.
Season 9, Episode 11 - The Opening Night Excitation
Aired December 17, 2015
After more than five years of dating, Sheldon and Amy spend their first night together. Also, Leonard, Wolowitz, and Koothrappali must decide who will take their extra Star Wars movie ticket.
Season 11, Episode 18 - The Gates Excitation
Aired March 29, 2018
Penny gets the opportunity to host Bill Gates at work when his company wants to partner with her pharmaceutical company. Also, Leonard, Koothrappali and Wolowitz do everything in their power to meet him, while Sheldon thinks he is the victim of an April Fools prank.