Aha!
The Big Bang Theory Season 7, Episode 2
Aha!
The Big Bang Theory Season 6, Episode 3
answer the door or should I
open it and say "AHA" again?
The Big Bang Theory Season 7, Episode 2
Aha!
The Big Bang Theory Season 7, Episode 3
Aha! Good question.
The Big Bang Theory Season 5, Episode 17