
Aha! Good question.
The Big Bang Theory Season 5, Episode 17

Aha!
The Big Bang Theory Season 7, Episode 2

No, I think it's stupid.
Aha!
The Big Bang Theory Season 7, Episode 16

Aha! So I am working with you?
The Big Bang Theory Season 3, Episode 4

A-ha! You are upset.
The Big Bang Theory Season 10, Episode 20