
He does this HYSTERICAL impersonation
of Stephen Hawking having phone sex.
The Big Bang Theory Season 2, Episode 11

That's HYSTERICAL.
The Big Bang Theory Season 7, Episode 15

Hysterical.
The Big Bang Theory Season 4, Episode 20

I also have a HYSTERICAL bit
planned for later
The Big Bang Theory Season 5, Episode 24

Yeah, it's HYSTERICAL.
The Big Bang Theory Season 4, Episode 22