Out of CURIOSITY...
The Big Bang Theory Season 1, Episode 17
Just out of CURIOSITY, why didn't you
ask Leonard for advice about this?
The Big Bang Theory Season 8, Episode 21
Where is the CURIOSITY?
The Big Bang Theory Season 4, Episode 21
Just out of CURIOSITY,
which one of you figured it out?
The Big Bang Theory Season 11, Episode 12
It's called
scientific CURIOSITY!
The Big Bang Theory Season 5, Episode 17