Please RSVP To The Birthday Extravaganza Of One Sheldon Cooper On The Big Bang Theory

There are plenty of reasons to party on The Big Bang Theory!

1. There are plenty of reasons to party on The Big Bang Theory!

After years of avoiding his birthday, Sheldon is finally convinced by Amy to celebrate turning one year older on the next episode of The Big Bang Theory—which also happens to be the series' 200th!—entitled "The Celebration Experimentation." 
Amy, Leonard, and Penny react to Sheldon not wanting to celebrate his birthday.

2. Amy, Leonard, and Penny react to Sheldon not wanting to celebrate his birthday.

"The Celebration Experimentation" (Episode 17, Season 9 of The Big Bang Theory)
Leonard and Stuart talk about planning the perfect party for Sheldon.

3. Leonard and Stuart talk about planning the perfect party for Sheldon.

"The Celebration Experimentation" (Episode 17, Season 9 of The Big Bang Theory)
Amy and Sheldon dress up for the happy occasion.

4. Amy and Sheldon dress up for the happy occasion.

"The Celebration Experimentation" (Episode 17, Season 9 of The Big Bang Theory)
Penny and Leonard visit with Beverly Hofstadter, who RSVP'd for Sheldon's soirée.

5. Penny and Leonard visit with Beverly Hofstadter, who RSVP'd for Sheldon's soirée.

"The Celebration Experimentation" (Episode 17, Season 9 of The Big Bang Theory)
Sheldon is all smiles when he arrives at his birthday party.

6. Sheldon is all smiles when he arrives at his birthday party.

"The Celebration Experimentation" (Episode 17, Season 9 of The Big Bang Theory)
With all the excitement, Sheldon almost didn't notice Adam West (aka Batman) was in attendance.

7. With all the excitement, Sheldon almost didn't notice Adam West (aka Batman) was in attendance.

"The Celebration Experimentation" (Episode 17, Season 9 of The Big Bang Theory)
Penny comforts Sheldon in the bathroom.

8. Penny comforts Sheldon in the bathroom.

"The Celebration Experimentation" (Episode 17, Season 9 of The Big Bang Theory)
Sheldon and Penny embrace on the big day.

9. Sheldon and Penny embrace on the big day.

"The Celebration Experimentation" (Episode 17, Season 9 of The Big Bang Theory)
Leonard gives a toast to his close friend and colleague, Sheldon.

10. Leonard gives a toast to his close friend and colleague, Sheldon.

"The Celebration Experimentation" (Episode 17, Season 9 of The Big Bang Theory)
Wil Wheaton also raises a cup in Sheldon's honor.

11. Wil Wheaton also raises a cup in Sheldon's honor.

"The Celebration Experimentation" (Episode 17, Season 9 of The Big Bang Theory)
It's not a party until someone sings

12. It's not a party until someone sings "Happy Birthday" and brings out a cake!

"The Celebration Experimentation" (Episode 17, Season 9 of The Big Bang Theory)
Happy 200th episode to the cast, crew, and fans of The Big Bang Theory!

13. Happy 200th episode to the cast, crew, and fans of The Big Bang Theory!

"The Celebration Experimentation" (Episode 17, Season 9 of The Big Bang Theory)

Watch all-new episodes of The Big Bang Theory on Thursdays at 8/7c.