
Aha!
The Big Bang Theory Season 7, Episode 2

Aha.
The Big Bang Theory Season 5, Episode 4

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

answer the door or should I
open it and say "AHA" again?
The Big Bang Theory Season 7, Episode 2

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